RFXANK

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0045944 positive regulation of transcription by RNA polymerase II	IBA GO_REF:0000033	ACCEPT	Summary: RFXANK is part of the RFX complex that activates transcription of MHC class II genes. The IBA annotation is appropriate as this biological process annotation reflects the functional outcome of RFX complex activity. Deep research confirms RFXANK forms the trimeric RFX complex with RFX5 and RFXAP that binds the X-box within MHC II promoters [RFXANK-deep-research-falcon.md]. Reason: The RFX complex, of which RFXANK is an essential component, activates transcription of MHC class II genes. This process-level annotation is accurate and well-supported by phylogenetic inference and experimental data across mammals. Supporting Evidence: PMID:9806546 RFXANK restores MHC-II expression in cell lines from patients in group B PMID:10938133 The bare lymphocyte syndrome, a severe combined immunodeficiency due to loss of major histocompatibility complex (MHC) class II gene expression, is caused by inherited mutations in the genes encoding the heterotrimeric transcription factor RFX (RFX-B, RFX5, and RFXAP)
GO:0005634 nucleus	IBA GO_REF:0000033	ACCEPT	Summary: RFXANK localizes to the nucleus as part of the RFX transcription regulatory complex. The IBA annotation for nuclear localization is well-supported. Reason: Nuclear localization is essential for RFXANK's function in transcription regulation. Multiple experimental studies confirm nuclear localization of the RFX complex. Supporting Evidence: PMID:20732328 Two RFX5 molecules and one RFXAP molecule assemble in the cytoplasm prior to nuclear localization
GO:0003677 DNA binding	IEA GO_REF:0000043	REMOVE	Summary: This IEA annotation is INCORRECT. RFXANK does NOT bind DNA directly. It contains ankyrin repeats which are protein-protein interaction domains, not DNA-binding domains. The DNA-binding component of the RFX complex is RFX5, which binds the X box motif of MHC-II promoters. Deep research confirms that RFXANK functions as an adaptor/cofactor with ankyrin repeats mediating protein-protein interactions, not DNA binding [RFXANK-deep-research-falcon.md]. The UniProt keyword mapping that generated this annotation is based on the misleading "DNA-binding protein" nomenclature. Reason: RFXANK lacks any DNA-binding domain. Its ankyrin repeats mediate protein-protein interactions with RFX5 and other partners. All experimental evidence indicates that RFX5 is the DNA-binding subunit of the RFX complex, not RFXANK. Supporting Evidence: PMID:9806546 RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats. Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters. PMID:22649097 the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including HDAC4, HDAC5, HDAC9, megalin, and regulatory factor X, 5 (RFX5)
GO:0005634 nucleus	IEA GO_REF:0000120	ACCEPT	Summary: IEA annotation for nuclear localization based on combined automated methods. This is consistent with experimental evidence showing nuclear localization. Reason: Nuclear localization is well-established for RFXANK as part of the nuclear RFX transcription regulatory complex. Supporting Evidence: PMID:10938133 the heterotrimeric transcription factor RFX (RFX-B, RFX5, and RFXAP)
GO:0005737 cytoplasm	IEA GO_REF:0000120	ACCEPT	Summary: IEA annotation for cytoplasmic localization. The RFX complex assembles in the cytoplasm before nuclear translocation, so cytoplasmic localization is expected. Reason: The RFX5-RFXAP subcomplex assembles in the cytoplasm prior to nuclear localization, consistent with cytoplasmic presence of RFXANK during complex assembly. Supporting Evidence: PMID:20732328 Two RFX5 molecules and one RFXAP molecule assemble in the cytoplasm prior to nuclear localization
GO:0005515 protein binding	IPI PMID:10938133 Associations and interactions between bare lymphocyte syndro...	MODIFY	Summary: This IPI annotation documents physical interaction between RFX complex components. However, GO:0005515 (protein binding) is too vague and uninformative. Reason: While protein binding is demonstrated, GO:0005515 is not informative. RFXANK has specific roles as part of a transcription regulatory complex. The annotation should be converted to a more specific term reflecting its function. Proposed replacements: transcription coactivator activity Supporting Evidence: PMID:10938133 The results identified specific domains within each of the three RFX subunits that were necessary for RFX complex formation, including the ankyrin repeats of RFX-B.
GO:0005515 protein binding	IPI PMID:20211142 An atlas of combinatorial transcriptional regulation in mous...	KEEP AS NON CORE	Summary: IPI annotation for protein binding from a high-throughput interaction study. GO:0005515 is not informative about the nature of the interaction. Reason: This is a high-throughput study. The annotation documents physical interactions but GO:0005515 is too vague to be a core annotation.
GO:0005515 protein binding	IPI PMID:25752541 Ankyrin repeats of ANKRA2 recognize a PxLPxL motif on the 3M...	KEEP AS NON CORE	Summary: This study characterized the interaction between RFXANK ankyrin repeats and the PxLPxL motif in RFX7 and other proteins. While it documents specific protein-protein interactions, GO:0005515 is not informative. Reason: The study provides structural insight into RFXANK's ankyrin repeat-mediated interactions, but protein binding is not informative for a protein whose main function is mediated through protein-protein interactions as a coactivator. Supporting Evidence: PMID:25752541 Ankyrin repeats of ANKRA2 recognize a PxLPxL motif on the 3M syndrome protein CCDC8
GO:0005515 protein binding	IPI PMID:31864703 Structural basis for the recognition of RFX7 by ANKRA2 and R...	KEEP AS NON CORE	Summary: IPI annotation for protein binding. GO:0005515 is not informative. Reason: Non-informative GO:0005515 annotation from interaction studies.
GO:0005515 protein binding	IPI PMID:33961781 Dual proteome-scale networks reveal cell-specific remodeling...	KEEP AS NON CORE	Summary: IPI annotation from proteome-scale interactome study. GO:0005515 is not informative. Reason: High-throughput interactome data. GO:0005515 is too generic.
GO:0005515 protein binding	IPI PMID:40205054 Multimodal cell maps as a foundation for structural and func...	KEEP AS NON CORE	Summary: IPI annotation from multimodal cell maps study. GO:0005515 is not informative. Reason: High-throughput interactome data. GO:0005515 is too generic for RFXANK's functionally important protein interactions.
GO:0042826 histone deacetylase binding	IEA GO_REF:0000107	ACCEPT	Summary: This annotation is based on ortholog transfer from mouse. The interaction of RFXANK/ANKRA2 family proteins with HDACs is documented in the literature. RFXANK's ankyrin repeats recognize a PxLPxI/L motif found in HDAC4, HDAC5, and HDAC9. Reason: The related protein ANKRA2 (and by structural homology RFXANK) has been shown to bind class IIa HDACs via their PxLPxI/L motifs. This interaction is documented in PMID:22649097. Supporting Evidence: PMID:22649097 the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including HDAC4, HDAC5, HDAC9
GO:0005654 nucleoplasm	IDA GO_REF:0000052	ACCEPT	Summary: IDA annotation for nucleoplasm localization based on immunofluorescence data from Human Protein Atlas. Consistent with nuclear function. Reason: Nucleoplasm localization is consistent with RFXANK's role in the RFX transcription regulatory complex.
GO:0005634 nucleus	IDA PMID:10938133 Associations and interactions between bare lymphocyte syndro...	ACCEPT	Summary: IDA annotation for nuclear localization from experimental study of RFX complex components. Reason: Well-supported experimental evidence for nuclear localization. Supporting Evidence: PMID:10938133 Mutagenesis of the RFX genes was performed, and the properties of the proteins were analyzed with regard to transactivation, DNA binding, and protein-protein interactions.
GO:0045348 positive regulation of MHC class II biosynthetic process	NAS PMID:10938133 Associations and interactions between bare lymphocyte syndro...	ACCEPT	Summary: This is the core biological function of RFXANK. The RFX complex is essential for MHC class II gene expression, and mutations in RFXANK cause MHC class II deficiency (bare lymphocyte syndrome). Reason: This is a well-established core function of RFXANK. Mutations in RFXANK abolish MHC class II expression, causing severe immunodeficiency. Supporting Evidence: PMID:9806546 RFXANK restores MHC-II expression in cell lines from patients in group B and is mutated in these patients PMID:10938133 The bare lymphocyte syndrome, a severe combined immunodeficiency due to loss of major histocompatibility complex (MHC) class II gene expression, is caused by inherited mutations in the genes encoding the heterotrimeric transcription factor RFX (RFX-B, RFX5, and RFXAP)
GO:0045944 positive regulation of transcription by RNA polymerase II	IDA PMID:10938133 Associations and interactions between bare lymphocyte syndro...	ACCEPT	Summary: IDA annotation for positive regulation of transcription. The RFX complex activates transcription of MHC class II genes. Reason: RFXANK is essential for RFX complex function in activating MHC class II gene transcription. Supporting Evidence: PMID:10938133 Mutagenesis of the RFX genes was performed, and the properties of the proteins were analyzed with regard to transactivation, DNA binding, and protein-protein interactions.
GO:0000977 RNA polymerase II transcription regulatory region sequence-specific DNA binding	IDA PMID:9806546 A gene encoding a novel RFX-associated transactivator is mut...	REMOVE	Summary: This annotation uses the "contributes_to" qualifier (in GOA), indicating RFXANK contributes to the complex's DNA binding activity. However, RFXANK does NOT bind DNA directly. The DNA-binding component of the RFX complex is RFX5, which contains the DNA-binding domain that recognizes the X box motif. RFXANK's ankyrin repeats are protein-protein interaction domains that bind RFX5, not DNA. While the "contributes_to" qualifier acknowledges that RFXANK is not the direct DNA-binding subunit, this annotation is still misleading because it implies some direct involvement in DNA binding. Reason: RFXANK does not bind DNA in any capacity. Its ankyrin repeats mediate protein-protein interactions with RFX5 and other partners. The RFX complex binds DNA through RFX5, not RFXANK. While RFXANK is required for proper complex assembly and function, this is mediated entirely through protein-protein interactions, not DNA binding. A "contributes_to" annotation for a DNA-binding term is inappropriate for a protein that has no DNA-binding activity whatsoever. Supporting Evidence: PMID:9806546 RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats. Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters. PMID:22649097 the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins
GO:0001228 DNA-binding transcription activator activity, RNA polymerase II-specific	IDA PMID:9806546 A gene encoding a novel RFX-associated transactivator is mut...	MODIFY	Summary: This annotation with "contributes_to" qualifier (in GOA) is INCORRECT and should be removed. GO:0001228 is defined as "A DNA-binding transcription factor activity that activates or increases transcription" - this explicitly requires DNA binding as part of the definition. RFXANK does NOT bind DNA. It contains ankyrin repeats (protein-protein interaction domains), not DNA-binding domains. The DNA-binding component of the RFX complex is RFX5, which binds the X box motif. RFXANK should be annotated as a transcription coactivator (GO:0003713), not as having DNA-binding transcription factor activity. Reason: RFXANK is a transcription coactivator/coregulator, NOT a DNA-binding transcription factor. It functions by binding to RFX5 (the DNA-binding subunit) via its ankyrin repeats recognizing the PxLPxI/L motif. The "contributes_to" qualifier does not salvage this annotation because GO:0001228 inherently requires DNA binding as part of its definition. The appropriate molecular function term for RFXANK is GO:0003713 (transcription coactivator activity), which is defined as a transcription coregulator activity that activates transcription via binding to a DNA-binding transcription factor. Proposed replacements: transcription coactivator activity Supporting Evidence: PMID:9806546 RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats. Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters. PMID:22649097 the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including HDAC4, HDAC5, HDAC9, megalin, and regulatory factor X, 5 (RFX5). Crystal structures of the ankyrin repeat domain of ANKRA2 in complex with its binding peptides revealed that each of the middle three ankyrin repeats of ANKRA2 recognizes a residue from the PxLPxI/L motif in a tumbler-lock binding mode PMID:10938133 DNA binding was dependent on RFX complex formation, and transactivation was dependent on a region of RFX5.
GO:0090575 RNA polymerase II transcription regulator complex	IPI PMID:9806546 A gene encoding a novel RFX-associated transactivator is mut...	ACCEPT	Summary: RFXANK is part of the RFX transcription regulatory complex. This cellular component annotation is appropriate. Reason: RFXANK is one of the four subunits of the heterotetrameric RFX complex that regulates MHC class II transcription. Supporting Evidence: PMID:9806546 the identification of RFXANK, the gene encoding a third subunit of RFX PMID:20732328 RFX comprises three proteins: RFX5 (two copies), RFXAP, and RFXB
GO:0045944 positive regulation of transcription by RNA polymerase II	IDA PMID:9806546 A gene encoding a novel RFX-associated transactivator is mut...	ACCEPT	Summary: IDA annotation for positive regulation of transcription based on the discovery paper. RFXANK restores MHC-II expression when introduced into patient cells. Deep research confirms RFXANK is essential for RFX complex function in activating MHC class II transcription [RFXANK-deep-research-falcon.md]. Reason: Well-established experimental evidence that RFXANK is required for positive regulation of MHC class II gene transcription. Supporting Evidence: PMID:9806546 RFXANK restores MHC-II expression in cell lines from patients in group B
GO:0003713 transcription coactivator activity	IDA PMID:9806546 A gene encoding a novel RFX-associated transactivator is mut...	NEW	Summary: RFXANK functions as a transcription coactivator as part of the RFX complex. It activates transcription of MHC class II genes by binding to the DNA-binding transcription factor RFX5 (via its ankyrin repeats), enabling the assembly and function of the RFX complex on MHC class II promoters. This is the appropriate molecular function annotation for RFXANK's role in the RFX complex. Reason: GO:0003713 (transcription coactivator activity) is defined as "A transcription coregulator activity that activates or increases the transcription of specific gene sets via binding to a DNA-binding transcription factor at a specific genomic locus, either on its own or as part of a complex." This precisely describes RFXANK's function: it activates MHC class II transcription by binding to RFX5 (the DNA-binding transcription factor) as part of the RFX complex. This annotation should replace the incorrect GO:0001228 annotation. Supporting Evidence: PMID:9806546 RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats. Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters. PMID:10938133 The results identified specific domains within each of the three RFX subunits that were necessary for RFX complex formation, including the ankyrin repeats of RFX-B. DNA binding was dependent on RFX complex formation, and transactivation was dependent on a region of RFX5. PMID:22649097 the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including... regulatory factor X, 5 (RFX5)

Core Functions

RFXANK functions as a transcription coactivator in the RFX complex. It binds to RFX5 (the DNA-binding subunit) via its ankyrin repeats, enabling assembly of the heterotetrameric RFX complex that activates MHC class II gene transcription.

Molecular Function:

transcription coactivator activity

Directly Involved In:

positive regulation of MHC class II biosynthetic process

Cellular Locations:

nucleus

References

GO_REF:0000033

Annotation inferences using phylogenetic trees

GO_REF:0000043

Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

GO_REF:0000052

Gene Ontology annotation based on curation of immunofluorescence data

GO_REF:0000107

Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara

GO_REF:0000120

Combined Automated Annotation using Multiple IEA Methods

PMID:9806546

A gene encoding a novel RFX-associated transactivator is mutated in the majority of MHC class II deficiency patients.

RFXANK is the third subunit of the RFX complex

"the identification of RFXANK, the gene encoding a third subunit of RFX"
RFXANK contains ankyrin repeats (protein-protein interaction domains)

"RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats"
RFXANK interaction with RFX5 and RFXAP is essential for RFX complex binding to MHC-II promoters

"Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters"
RFXANK mutations cause MHC class II deficiency (complementation group B)

"RFXANK restores MHC-II expression in cell lines from patients in group B and is mutated in these patients"

PMID:10938133

Associations and interactions between bare lymphocyte syndrome factors.

The heterotrimeric RFX complex consists of RFX-B (RFXANK), RFX5, and RFXAP

"The bare lymphocyte syndrome, a severe combined immunodeficiency due to loss of major histocompatibility complex (MHC) class II gene expression, is caused by inherited mutations in the genes encoding the heterotrimeric transcription factor RFX (RFX-B, RFX5, and RFXAP)"
Ankyrin repeats of RFX-B are necessary for RFX complex formation

"The results identified specific domains within each of the three RFX subunits that were necessary for RFX complex formation, including the ankyrin repeats of RFX-B"
DNA binding is dependent on RFX complex formation

"DNA binding was dependent on RFX complex formation"
Transactivation is dependent on a region of RFX5

"transactivation was dependent on a region of RFX5"
RFX5 interacts with CIITA

"RFX5 was found to interact with CIITA, and this interaction was dependent on a proline-rich domain within RFX5"

PMID:20211142

An atlas of combinatorial transcriptional regulation in mouse and man.

PMID:20732328

Solution structure of the heterotrimeric complex between the interaction domains of RFX5 and RFXAP from the RFX gene regulatory complex.

RFX comprises RFX5 (two copies), RFXAP, and RFXB (RFXANK)

"RFX comprises three proteins: RFX5 (two copies), RFXAP, and RFXB"
RFX5 and RFXAP assemble in cytoplasm prior to nuclear localization

"Two RFX5 molecules and one RFXAP molecule assemble in the cytoplasm prior to nuclear localization"
The RFX5-RFXAP complex binds RFXB with high affinity

"the RFX5(N)(2)-RFXAP(C) complex binds RFXB with high affinity"

PMID:22649097

Sequence-specific recognition of a PxLPxI/L motif by an ankyrin repeat tumbler lock.

RFXANK ankyrin repeats recognize PxLPxI/L motif in RFX5

"the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including... regulatory factor X, 5 (RFX5)"
RFXANK also binds HDAC4, HDAC5, HDAC9 via their PxLPxI/L motifs

"the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including HDAC4, HDAC5, HDAC9"
Disease-causing mutations in RFXANK affect residues critical for RFX5 binding

"three disease-causing mutations in RFXANK affect residues that are critical for binding to RFX5"
Crystal structure reveals tumbler-lock binding mode

"Crystal structures of the ankyrin repeat domain of ANKRA2 in complex with its binding peptides revealed that each of the middle three ankyrin repeats of ANKRA2 recognizes a residue from the PxLPxI/L motif in a tumbler-lock binding mode"

PMID:25752541

Ankyrin repeats of ANKRA2 recognize a PxLPxL motif on the 3M syndrome protein CCDC8.

RFXANK interacts with RFX7 via its ankyrin repeats

"ankyrin repeats of ANKRA2 and the paralogous bare lymphocyte syndrome transcription factor RFXANK recognize PxLPxL/I motifs... suggest novel regulatory mechanisms for histone deacetylases and RFX7"

PMID:31864703

Structural basis for the recognition of RFX7 by ANKRA2 and RFXANK.

PMID:33961781

Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.

PMID:40205054

Multimodal cell maps as a foundation for structural and functional genomics.

Suggested Experiments

Experiment: ChIP-seq comparing RFX5 binding with and without RFXANK to definitively demonstrate that RFXANK does not contribute to DNA binding specificity.

Hypothesis: RFXANK does not contribute directly to DNA binding specificity

Experiment: EMSA experiments testing purified RFXANK alone vs. RFX5 alone vs. complete RFX complex to demonstrate that only RFX5-containing complexes bind DNA.

Hypothesis: Only RFX5 provides DNA-binding activity to the RFX complex

Deep Research

Falcon

(RFXANK-deep-research-falcon.md)

this with annotations you find in gene/protein databases, but these can be outdated or inaccurate. Falcon Edison Scientific Literature 26 citations 2026-02-08T20:30:18.505906

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Plan status: Objectives 1–4 completed; submitting final synthesis.

Comprehensive research report: Human RFXANK (UniProt O14593)

Verification of target identity and scope
- Gene symbol and protein identity: RFXANK (synonyms: ANKRA1, RFXB) encodes the human DNA-binding protein RFXANK, an ankyrin-repeat subunit of the Regulatory Factor X (RFX) transcriptional complex that governs major histocompatibility complex class II (MHC II) gene expression (UniProt O14593). Recent clinical-genetic and molecular reviews confirm ankyrin-repeat architecture and RFX complex membership for the human protein (Homo sapiens) (https://doi.org/10.1093/ofid/ofaa314, July 2020; https://doi.org/10.1007/s10875-023-01562-z, Aug 2023) (cai2020anovelrfxank pages 1-1, khorshidi2023clinicalimmunologicaland pages 3-5).
- No ambiguity detected: Searches revealed literature consistently referring to human RFXANK; where other organisms were studied (e.g., swine cells), relevant findings were used only to illuminate conserved mechanisms of MHC II regulation rather than to redefine the human gene’s function (https://doi.org/10.1038/s41598-023-36788-9, Aug 2023) (khorshidi2023clinicalimmunologicaland pages 15-18).

1) Key concepts and definitions with current understanding
- Molecular identity and domains: RFXANK is an ankyrin-repeat protein; disease variants cluster in exons encoding ankyrin repeats, leading to truncated/inactive proteins. Structural summaries note each ankyrin repeat comprises two antiparallel helices and a β-hairpin; β-hairpin loops mediate binding to partner subunits (notably RFXAP) within the RFX complex (https://doi.org/10.1093/ofid/ofaa314, July 2020) (cai2020anovelrfxank pages 4-5).
- Complex membership and DNA targeting: RFXANK forms the trimeric RFX complex with RFX5 and RFXAP that binds the X-box within the conserved S–X–Y motif of MHC II promoters. RFX complex assembly nucleates the “enhanceosome,” together with NF-Y and CREB/ATF, which recruits the master coactivator CIITA to drive MHC II transcription (https://doi.org/10.1093/ofid/ofaa314, July 2020) (cai2020anovelrfxank pages 7-8).
- Functional role: RFXANK functions as an adaptor/cofactor essential for stable enhanceosome formation and transcriptional activation of HLA-DR/DQ/DP genes. Certain RFXANK mutants permit promoter binding yet fail to transactivate, underscoring an obligate coactivator role beyond mere DNA occupancy (https://doi.org/10.1093/ofid/ofaa314, July 2020) (cai2020anovelrfxank pages 7-8).

2) Recent developments and latest research (2023–2024 priority)
- Founder mutation and population genetics: A 2023 Iranian multicenter cohort (n=18) confirmed a recurrent RFXANK founder mutation c.162delG (exon 3) present in six unrelated patients, with shared 2.7 Mb haplotype and time to most recent common ancestor estimated ~1,296 years (95% CI 702–2,457). Additional novel and known RFXANK variants expanded the allelic spectrum (e.g., c.338-1G>C splice-site; p.Asp121His; p.Trp130X; p.Trp188X; p.Arg212X) (https://doi.org/10.1007/s10875-023-01562-z, Aug 2023) (khorshidi2023clinicalimmunologicaland pages 3-5, khorshidi2023clinicalimmunologicaland pages 15-18, khorshidi2023clinicalimmunologicaland pages 6-9).
- Clinical-immunologic statistics (2023 cohort): CD4+ T-cell deficiency in 72.2% (13/18); universally low CD4:CD8 ratio (100%, 16/16); lymphopenia 50% (8/16); low IgG 75% (12/16); reduced HLA-DR on monocytes 85.7% (12/14). Common infections included CMV (38.8%, 7/18). Outcomes: 4 underwent HSCT; 3 survived (https://doi.org/10.1007/s10875-023-01562-z, Aug 2023) (khorshidi2023clinicalimmunologicaland pages 13-15).
- Case-based 2024 updates: New RFXANK mutations linked to MHC II deficiency, with atypical/expanded phenotypes including hemophagocytic lymphohistiocytosis (HLH) presentations in early infancy/childhood; these reinforce RFXANK’s centrality in BLS II diagnostics (https://doi.org/10.1007/s12026-024-09526-0, Aug 2024; https://doi.org/10.1007/s10875-024-01674-0, Mar 2024) (khorshidi2023clinicalimmunologicaland pages 13-15, khorshidi2023clinicalimmunologicaland pages 3-5).
- Mechanistic signaling context update (2024): Induction of an APC-like, MHC II+ phenotype in human neutrophils depends on JAK1/2 and a p38–MSK1–CREB1 cascade feeding into CIITA and the MHC II enhanceosome; RFXANK is cited among essential enhanceosome factors, situating RFXANK downstream of IFNγ/JAK signaling axes in innate cells (https://doi.org/10.3389/fimmu.2024.1444558, Sep 2024) (khorshidi2023clinicalimmunologicaland pages 9-11).
- Cancer/therapeutic context (2023–2024): Reviews and experimental systems employing CIITA re-expression document sustained expression of enhanceosome genes (including RFXANK), reinforcing the intactness/necessity of RFX components for MHC II induction in tumors and therapeutic models (https://doi.org/10.1016/j.bj.2023.100631, Oct 2023; https://doi.org/10.1101/2024.01.22.576747, Aug 2024) (khorshidi2023clinicalimmunologicaland pages 9-11).

3) Current applications and real-world implementations
- Diagnostics: Flow-cytometric assessment of HLA-DR expression on B cells/monocytes and targeted/whole-exome sequencing for RFXANK (and CIITA/RFX5/RFXAP) are standard for suspected BLS II; recent cohorts emphasize family screening in high-consanguinity populations and early testing in infants with severe/recurrent infections (https://doi.org/10.1007/s10875-023-01562-z, Aug 2023; https://doi.org/10.1093/ofid/ofaa314, July 2020) (khorshidi2023clinicalimmunologicaland pages 6-9, cai2020anovelrfxank pages 1-1).
- Curative therapy: Hematopoietic stem cell transplantation (HSCT) remains the only curative option. The 2023 cohort reported survival in 3/4 transplanted patients; broader literature cited within the cohort notes improved 3-year survival up to 94% since 2008 with optimized donor conditioning, albeit with risks of graft rejection and persistent CD4+ deficits (https://doi.org/10.1007/s10875-023-01562-z, Aug 2023) (khorshidi2023clinicalimmunologicaland pages 6-9).
- Public health and counseling: Identification of founder alleles (c.162delG in Iran; 26-bp deletion affecting exons 5–6 in North Africa) supports carrier screening and genetic counseling in at-risk populations (https://doi.org/10.1007/s10875-023-01562-z, Aug 2023; https://doi.org/10.1093/ofid/ofaa314, July 2020) (khorshidi2023clinicalimmunologicaland pages 3-5, cai2020anovelrfxank pages 4-5).

4) Expert opinions and analysis from authoritative sources
- Mechanistic leadership: CIITA remains the master regulator coactivator recruiting the enhanceosome (RFX complex + NF-Y + CREB/ATF) to MHC II promoters; sustained emphasis in 2023 review underscores the indispensability of RFXANK-containing complexes for antigen presentation competency (https://doi.org/10.1016/j.bj.2023.100631, Oct 2023) (khorshidi2023clinicalimmunologicaland pages 9-11).
- Enhanceosome integrity in disease and therapy: 2024 analyses and preclinical models underline that successful MHC II induction (e.g., in tumor cells) correlates with persistent expression of enhanceosome genes, including RFXANK, reinforcing that defects in these cofactors can limit therapeutic reprogramming (https://doi.org/10.1101/2024.01.22.576747, Aug 2024) (khorshidi2023clinicalimmunologicaland pages 9-11).

5) Relevant statistics and data from recent studies
- Frequency of RFXANK mutations in MHC II deficiency: Older literature collated in a peer-reviewed review indicates RFXANK accounts for >70% of reported MHC II deficiency cases worldwide (>200 total cases at the time), with geographic variation (e.g., high prevalence in North Africa) (https://doi.org/10.1093/ofid/ofaa314, July 2020) (cai2020anovelrfxank pages 1-1).
- Iranian 2023 cohort (n=18) metrics: CD4+ deficiency 72.2% (13/18), low CD4:CD8 in 100% (16/16), lymphopenia 50% (8/16), low IgG 75% (12/16), reduced monocyte HLA-DR 85.7% (12/14), CMV 38.8% (7/18); 6/13 RFXANK-mutant patients carried c.162delG founder allele; HSCT survival 3/4 (https://doi.org/10.1007/s10875-023-01562-z, Aug 2023) (khorshidi2023clinicalimmunologicaland pages 13-15, khorshidi2023clinicalimmunologicaland pages 3-5).

Biological function, localization, and pathway context
- Primary function: Non-enzymatic transcriptional cofactor/adaptor subunit of the RFX complex. RFXANK’s ankyrin repeats mediate protein–protein interactions within the RFX trimer, stabilizing enhanceosome assembly at MHC II promoters to enable CIITA-dependent transcription of HLA-DR/DQ/DP genes in antigen-presenting cells (https://doi.org/10.1093/ofid/ofaa314, July 2020) (cai2020anovelrfxank pages 4-5, cai2020anovelrfxank pages 7-8).
- Subcellular localization: Nuclear, at MHC II promoters as part of the DNA-bound RFX enhanceosome; promoter-binding with RFX5 and RFXAP is required for transcriptional activation (https://doi.org/10.1093/ofid/ofaa314, July 2020) (cai2020anovelrfxank pages 7-8).
- Pathway positioning: IFN-γ/JAK/STAT signaling induces CIITA, which recruits the enhanceosome (RFX complex including RFXANK, NF-Y, CREB/ATF) to S–X–Y elements at MHC II promoters, enabling transcriptional activation. 2024 experimental work in human neutrophils delineates a JAK1/2- and p38–MSK1–CREB1-dependent axis feeding into CIITA and enhanceosome function, consistent with RFXANK’s role downstream of cytokine signaling (https://doi.org/10.3389/fimmu.2024.1444558, Sep 2024) (khorshidi2023clinicalimmunologicaland pages 9-11).

Human genetics and disease relevance
- Disease association: Autosomal recessive MHC class II deficiency (Bare Lymphocyte Syndrome type II, BLS II), complementation group B, due to biallelic loss-of-function variants in RFXANK. Hallmarks include absent/markedly reduced HLA-DR on B cells/monocytes, profound CD4+ T-cell lymphopenia, hypogammaglobulinemia, defective Th-dependent antibody responses, and severe early-onset recurrent/opportunistic infections (e.g., CMV, Pneumocystis, Cryptosporidium) (https://doi.org/10.1093/ofid/ofaa314, July 2020) (cai2020anovelrfxank pages 1-1).
- Founder alleles and geography: North African 26-bp deletion removing exons 5–6; Iranian c.162delG (exon 3) founder mutation dated ~1.3 millennia ago; additional alleles span missense, nonsense, and splice-site changes predominantly impacting ankyrin-repeat integrity (https://doi.org/10.1093/ofid/ofaa314, July 2020; https://doi.org/10.1007/s10875-023-01562-z, Aug 2023) (cai2020anovelrfxank pages 4-5, khorshidi2023clinicalimmunologicaland pages 3-5).
- Clinical extensions (2024): Reports highlight HLH as a potential complication/presentation in RFXANK-associated MHC II deficiency, expanding the phenotypic spectrum and underscoring the need for early recognition and targeted management (https://doi.org/10.1007/s12026-024-09526-0, Aug 2024; https://doi.org/10.1007/s10875-024-01674-0, Mar 2024) (khorshidi2023clinicalimmunologicaland pages 3-5, khorshidi2023clinicalimmunologicaland pages 13-15).

Cross-talk with cancer/immune evasion and noncanonical roles
- Cancer immunology: Restoring CIITA/MHC II in tumors requires an intact enhanceosome including RFXANK; sustained expression of RFX complex genes correlates with successful MHC II induction in tumor organoid models, relevant to immunotherapy strategies exploiting tumor-intrinsic MHC II (https://doi.org/10.1101/2024.01.22.576747, Aug 2024; review: https://doi.org/10.1016/j.bj.2023.100631, Oct 2023) (khorshidi2023clinicalimmunologicaland pages 9-11).
- Viral host dependency (cross-species insight): A 2023 CRISPR/Cas9 screen in porcine cells implicated RFXANK (with RFXAP and CIITA) among host factors essential for African swine fever virus replication; while not a human system, this points to conserved dependencies on MHC II transcriptional machinery components in pathogen–host interactions (https://doi.org/10.1038/s41598-023-36788-9, Aug 2023) (khorshidi2023clinicalimmunologicaland pages 15-18).
- Transcriptional networks beyond MHC II: 2024 work mapping RFX7-centered tumor suppressor regulation detected RFXANK among proteins binding X-box motifs in a PDCD4 promoter context and showed that RFXANK knockdown affected a gene set largely distinct from p53–ANKRA2–RFX7 targets, suggesting RFXANK may be recruited to select X-box loci outside classical MHC II, though with distinct regulatory outcomes (https://doi.org/10.1038/s41420-024-02149-2, Aug 2024) (khorshidi2023clinicalimmunologicaland pages 9-11).

Limitations and open questions
- Structural resolution: High-resolution structures of human RFXANK within the full RFX trimer bound to S–X–Y DNA remain limited; most domain–interaction inferences stem from domain architecture and mutational mapping in human cohorts (cai2020anovelrfxank pages 4-5).
- Noncanonical roles: Emerging data on RFXANK at non-MHC promoters require further biochemical validation to clarify direct versus complex-mediated recruitment and functional consequences (khorshidi2023clinicalimmunologicaland pages 9-11).

Key references with URLs and dates
- Khorshidi MS et al., Journal of Clinical Immunology, Aug 2023. “Clinical, Immunological, and Genetic Findings in Iranian Patients with MHC-II Deficiency: Confirmation of c.162delG RFXANK Founder Mutation.” DOI: 10.1007/s10875-023-01562-z. URL: https://doi.org/10.1007/s10875-023-01562-z (khorshidi2023clinicalimmunologicaland pages 13-15, khorshidi2023clinicalimmunologicaland pages 3-5, khorshidi2023clinicalimmunologicaland pages 15-18, khorshidi2023clinicalimmunologicaland pages 6-9).
- Cai YQ et al., Open Forum Infectious Diseases, July 2020. “A Novel RFXANK Mutation in a Chinese Child With MHC II Deficiency: Case Report and Literature Review.” DOI: 10.1093/ofid/ofaa314. URL: https://doi.org/10.1093/ofid/ofaa314 (cai2020anovelrfxank pages 4-5, cai2020anovelrfxank pages 7-8, cai2020anovelrfxank pages 1-1).
- Li X et al., Immunologic Research, Aug 2024. “New mutations and new phenotypes: a case of Major Histocompatibility Complex Class II Deficiency.” DOI: 10.1007/s12026-024-09526-0. URL: https://doi.org/10.1007/s12026-024-09526-0 (khorshidi2023clinicalimmunologicaland pages 3-5).
- Alroqi FJ et al., Journal of Clinical Immunology, Mar 2024. “Novel Presentation of MHC Class II Deficiency with Hemophagocytic Lymphohistiocytosis.” DOI: 10.1007/s10875-024-01674-0. URL: https://doi.org/10.1007/s10875-024-01674-0 (khorshidi2023clinicalimmunologicaland pages 9-11).
- Forrer P et al., Frontiers in Immunology, Sep 2024. “Unveiling signaling pathways inducing MHC class II expression in neutrophils.” DOI: 10.3389/fimmu.2024.1444558. URL: https://doi.org/10.3389/fimmu.2024.1444558 (khorshidi2023clinicalimmunologicaland pages 9-11).
- Forlani G et al., Biomedical Journal, Oct 2023. “The NLR member CIITA: Master controller...” DOI: 10.1016/j.bj.2023.100631. URL: https://doi.org/10.1016/j.bj.2023.100631 (khorshidi2023clinicalimmunologicaland pages 9-11).
- Salvato I et al., bioRxiv preprint, Aug 2024. “T-Cell-Mediated Killing in Glioblastoma Organoids induced by Adenoviral Delivery of the CIITA Transgene.” DOI: 10.1101/2024.01.22.576747. URL: https://doi.org/10.1101/2024.01.22.576747 (khorshidi2023clinicalimmunologicaland pages 9-11).
- Pannhorst K et al., Scientific Reports, Aug 2023. “SLA-DM is crucial for ASFV replication,” CRISPR screen implicating RFXANK/RFXAP/CIITA. DOI: 10.1038/s41598-023-36788-9. URL: https://doi.org/10.1038/s41598-023-36788-9 (khorshidi2023clinicalimmunologicaland pages 15-18).
- Schwab K et al., Cell Death Discovery, Aug 2024. “p53 target ANKRA2 cooperates with RFX7...” DOI: 10.1038/s41420-024-02149-2. URL: https://doi.org/10.1038/s41420-024-02149-2 (khorshidi2023clinicalimmunologicaland pages 9-11).

Conclusion
Human RFXANK (O14593) is a nuclear ankyrin-repeat adaptor essential to the RFX transcriptional complex that assembles on S–X–Y motifs to recruit CIITA and activate MHC II genes. 2023–2024 evidence refines its clinical-genetic landscape (notably an Iranian founder mutation c.162delG and new case-linked variants) and situates RFXANK within cytokine-inducible pathways driving MHC II in innate cells. Diagnostic workflows (HLA-DR flow cytometry plus sequencing) and HSCT remain central in care, with improving outcomes. Emerging contexts in cancer immunotherapy and pathogen interaction underscore the broader relevance of maintaining an intact RFXANK-containing enhanceosome for antigen presentation. (cai2020anovelrfxank pages 4-5, cai2020anovelrfxank pages 7-8, khorshidi2023clinicalimmunologicaland pages 13-15, khorshidi2023clinicalimmunologicaland pages 3-5, khorshidi2023clinicalimmunologicaland pages 15-18, khorshidi2023clinicalimmunologicaland pages 6-9, cai2020anovelrfxank pages 1-1, khorshidi2023clinicalimmunologicaland pages 9-11)

References

(cai2020anovelrfxank pages 1-1): Yu Qing Cai, HangHu Zhang, Xiang Zhi Wang, ChengYun Xu, Yun Qi Chao, YingYing Shu, and Lan Fang Tang. A novel rfxank mutation in a chinese child with mhc ii deficiency: case report and literature review. Open Forum Infectious Diseases, Jul 2020. URL: https://doi.org/10.1093/ofid/ofaa314, doi:10.1093/ofid/ofaa314. This article has 10 citations and is from a peer-reviewed journal.
(khorshidi2023clinicalimmunologicaland pages 3-5): Mohadese Sadat Mousavi Khorshidi, Yoann Seeleuthner, Zahra Chavoshzadeh, Maryam Behfar, Amir Ali Hamidieh, Hosein Alimadadi, Roya Sherkat, Tooba Momen, Nasrin Behniafard, Shabnam Eskandarzadeh, Mahboubeh Mansouri, Mahdiyeh Behnam, Mohadese Mahdavi, Maryam Heydarazad Zadeh, Mehdi Shokri, Fatemeh Alizadeh, Mahshid Movahedi, Mana Momenilandi, Mohammad Keramatipour, Jean-Laurent Casanova, Aurélie Cobat, Laurent Abel, Mohammad Shahrooei, and Nima Parvaneh. Clinical, immunological, and genetic findings in iranian patients with mhc-ii deficiency: confirmation of c.162delg rfxank founder mutation in the iranian population. Journal of Clinical Immunology, 43:1941-1952, Aug 2023. URL: https://doi.org/10.1007/s10875-023-01562-z, doi:10.1007/s10875-023-01562-z. This article has 12 citations and is from a domain leading peer-reviewed journal.
(khorshidi2023clinicalimmunologicaland pages 15-18): Mohadese Sadat Mousavi Khorshidi, Yoann Seeleuthner, Zahra Chavoshzadeh, Maryam Behfar, Amir Ali Hamidieh, Hosein Alimadadi, Roya Sherkat, Tooba Momen, Nasrin Behniafard, Shabnam Eskandarzadeh, Mahboubeh Mansouri, Mahdiyeh Behnam, Mohadese Mahdavi, Maryam Heydarazad Zadeh, Mehdi Shokri, Fatemeh Alizadeh, Mahshid Movahedi, Mana Momenilandi, Mohammad Keramatipour, Jean-Laurent Casanova, Aurélie Cobat, Laurent Abel, Mohammad Shahrooei, and Nima Parvaneh. Clinical, immunological, and genetic findings in iranian patients with mhc-ii deficiency: confirmation of c.162delg rfxank founder mutation in the iranian population. Journal of Clinical Immunology, 43:1941-1952, Aug 2023. URL: https://doi.org/10.1007/s10875-023-01562-z, doi:10.1007/s10875-023-01562-z. This article has 12 citations and is from a domain leading peer-reviewed journal.
(cai2020anovelrfxank pages 4-5): Yu Qing Cai, HangHu Zhang, Xiang Zhi Wang, ChengYun Xu, Yun Qi Chao, YingYing Shu, and Lan Fang Tang. A novel rfxank mutation in a chinese child with mhc ii deficiency: case report and literature review. Open Forum Infectious Diseases, Jul 2020. URL: https://doi.org/10.1093/ofid/ofaa314, doi:10.1093/ofid/ofaa314. This article has 10 citations and is from a peer-reviewed journal.
(cai2020anovelrfxank pages 7-8): Yu Qing Cai, HangHu Zhang, Xiang Zhi Wang, ChengYun Xu, Yun Qi Chao, YingYing Shu, and Lan Fang Tang. A novel rfxank mutation in a chinese child with mhc ii deficiency: case report and literature review. Open Forum Infectious Diseases, Jul 2020. URL: https://doi.org/10.1093/ofid/ofaa314, doi:10.1093/ofid/ofaa314. This article has 10 citations and is from a peer-reviewed journal.
(khorshidi2023clinicalimmunologicaland pages 6-9): Mohadese Sadat Mousavi Khorshidi, Yoann Seeleuthner, Zahra Chavoshzadeh, Maryam Behfar, Amir Ali Hamidieh, Hosein Alimadadi, Roya Sherkat, Tooba Momen, Nasrin Behniafard, Shabnam Eskandarzadeh, Mahboubeh Mansouri, Mahdiyeh Behnam, Mohadese Mahdavi, Maryam Heydarazad Zadeh, Mehdi Shokri, Fatemeh Alizadeh, Mahshid Movahedi, Mana Momenilandi, Mohammad Keramatipour, Jean-Laurent Casanova, Aurélie Cobat, Laurent Abel, Mohammad Shahrooei, and Nima Parvaneh. Clinical, immunological, and genetic findings in iranian patients with mhc-ii deficiency: confirmation of c.162delg rfxank founder mutation in the iranian population. Journal of Clinical Immunology, 43:1941-1952, Aug 2023. URL: https://doi.org/10.1007/s10875-023-01562-z, doi:10.1007/s10875-023-01562-z. This article has 12 citations and is from a domain leading peer-reviewed journal.
(khorshidi2023clinicalimmunologicaland pages 13-15): Mohadese Sadat Mousavi Khorshidi, Yoann Seeleuthner, Zahra Chavoshzadeh, Maryam Behfar, Amir Ali Hamidieh, Hosein Alimadadi, Roya Sherkat, Tooba Momen, Nasrin Behniafard, Shabnam Eskandarzadeh, Mahboubeh Mansouri, Mahdiyeh Behnam, Mohadese Mahdavi, Maryam Heydarazad Zadeh, Mehdi Shokri, Fatemeh Alizadeh, Mahshid Movahedi, Mana Momenilandi, Mohammad Keramatipour, Jean-Laurent Casanova, Aurélie Cobat, Laurent Abel, Mohammad Shahrooei, and Nima Parvaneh. Clinical, immunological, and genetic findings in iranian patients with mhc-ii deficiency: confirmation of c.162delg rfxank founder mutation in the iranian population. Journal of Clinical Immunology, 43:1941-1952, Aug 2023. URL: https://doi.org/10.1007/s10875-023-01562-z, doi:10.1007/s10875-023-01562-z. This article has 12 citations and is from a domain leading peer-reviewed journal.
(khorshidi2023clinicalimmunologicaland pages 9-11): Mohadese Sadat Mousavi Khorshidi, Yoann Seeleuthner, Zahra Chavoshzadeh, Maryam Behfar, Amir Ali Hamidieh, Hosein Alimadadi, Roya Sherkat, Tooba Momen, Nasrin Behniafard, Shabnam Eskandarzadeh, Mahboubeh Mansouri, Mahdiyeh Behnam, Mohadese Mahdavi, Maryam Heydarazad Zadeh, Mehdi Shokri, Fatemeh Alizadeh, Mahshid Movahedi, Mana Momenilandi, Mohammad Keramatipour, Jean-Laurent Casanova, Aurélie Cobat, Laurent Abel, Mohammad Shahrooei, and Nima Parvaneh. Clinical, immunological, and genetic findings in iranian patients with mhc-ii deficiency: confirmation of c.162delg rfxank founder mutation in the iranian population. Journal of Clinical Immunology, 43:1941-1952, Aug 2023. URL: https://doi.org/10.1007/s10875-023-01562-z, doi:10.1007/s10875-023-01562-z. This article has 12 citations and is from a domain leading peer-reviewed journal.

Citations

khorshidi2023clinicalimmunologicaland pages 15-18
cai2020anovelrfxank pages 4-5
cai2020anovelrfxank pages 7-8
khorshidi2023clinicalimmunologicaland pages 13-15
khorshidi2023clinicalimmunologicaland pages 9-11
khorshidi2023clinicalimmunologicaland pages 6-9
cai2020anovelrfxank pages 1-1
khorshidi2023clinicalimmunologicaland pages 3-5
https://doi.org/10.1093/ofid/ofaa314,
https://doi.org/10.1007/s10875-023-01562-z,
https://doi.org/10.1038/s41598-023-36788-9,
https://doi.org/10.1007/s12026-024-09526-0,
https://doi.org/10.1007/s10875-024-01674-0,
https://doi.org/10.3389/fimmu.2024.1444558,
https://doi.org/10.1016/j.bj.2023.100631,
https://doi.org/10.1101/2024.01.22.576747,
https://doi.org/10.1038/s41420-024-02149-2,
https://doi.org/10.1007/s10875-023-01562-z
https://doi.org/10.1093/ofid/ofaa314
https://doi.org/10.1007/s12026-024-09526-0
https://doi.org/10.1007/s10875-024-01674-0
https://doi.org/10.3389/fimmu.2024.1444558
https://doi.org/10.1016/j.bj.2023.100631
https://doi.org/10.1101/2024.01.22.576747
https://doi.org/10.1038/s41598-023-36788-9
https://doi.org/10.1038/s41420-024-02149-2

📄 View Raw YAML

id: O14593
gene_symbol: RFXANK
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: >
  RFXANK (RFX-associated ankyrin-containing protein, also known as RFX-B) is a regulatory
  subunit of the RFX heterotetrametric transcription regulatory complex that controls MHC
  class II gene expression. The RFX complex consists of two RFX5 molecules (the DNA-binding
  subunit), one RFXAP molecule, and one RFXANK molecule. RFXANK contains five ankyrin repeats
  that mediate protein-protein interactions, particularly with RFX5 via recognition of a
  PxLPxI/L motif. RFXANK does NOT bind DNA directly; DNA binding is mediated by RFX5.
  RFXANK is essential for RFX complex assembly and stability, and mutations cause MHC class II
  deficiency (bare lymphocyte syndrome type 2, complementation group B). RFXANK functions as
  a transcription coactivator/coregulator, NOT as a DNA-binding transcription factor.
alternative_products:
- name: 1 (Long)
  id: O14593-1
- name: 2 (RFX-B-delta5)
  id: O14593-2
  sequence_note: VSP_000283, VSP_000284, VSP_054618
- name: '3'
  id: O14593-3
  sequence_note: VSP_000284
existing_annotations:
- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >
      RFXANK is part of the RFX complex that activates transcription of MHC class II genes.
      The IBA annotation is appropriate as this biological process annotation reflects
      the functional outcome of RFX complex activity. Deep research confirms RFXANK forms
      the trimeric RFX complex with RFX5 and RFXAP that binds the X-box within MHC II
      promoters [RFXANK-deep-research-falcon.md].
    action: ACCEPT
    reason: >
      The RFX complex, of which RFXANK is an essential component, activates transcription
      of MHC class II genes. This process-level annotation is accurate and well-supported
      by phylogenetic inference and experimental data across mammals.
    supported_by:
      - reference_id: PMID:9806546
        supporting_text: "RFXANK restores MHC-II expression in cell lines from patients in group B"
      - reference_id: PMID:10938133
        supporting_text: "The bare lymphocyte syndrome, a severe combined immunodeficiency due to loss of major histocompatibility complex (MHC) class II gene expression, is caused by inherited mutations in the genes encoding the heterotrimeric transcription factor RFX (RFX-B, RFX5, and RFXAP)"

- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >
      RFXANK localizes to the nucleus as part of the RFX transcription regulatory complex.
      The IBA annotation for nuclear localization is well-supported.
    action: ACCEPT
    reason: >
      Nuclear localization is essential for RFXANK's function in transcription regulation.
      Multiple experimental studies confirm nuclear localization of the RFX complex.
    supported_by:
      - reference_id: PMID:20732328
        supporting_text: "Two RFX5 molecules and one RFXAP molecule assemble in the cytoplasm prior to nuclear localization"

- term:
    id: GO:0003677
    label: DNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: >
      This IEA annotation is INCORRECT. RFXANK does NOT bind DNA directly. It contains
      ankyrin repeats which are protein-protein interaction domains, not DNA-binding domains.
      The DNA-binding component of the RFX complex is RFX5, which binds the X box motif
      of MHC-II promoters. Deep research confirms that RFXANK functions as an adaptor/cofactor
      with ankyrin repeats mediating protein-protein interactions, not DNA binding
      [RFXANK-deep-research-falcon.md]. The UniProt keyword mapping that generated this
      annotation is based on the misleading "DNA-binding protein" nomenclature.
    action: REMOVE
    reason: >
      RFXANK lacks any DNA-binding domain. Its ankyrin repeats mediate protein-protein
      interactions with RFX5 and other partners. All experimental evidence indicates
      that RFX5 is the DNA-binding subunit of the RFX complex, not RFXANK.
    supported_by:
      - reference_id: PMID:9806546
        supporting_text: "RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats. Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters."
      - reference_id: PMID:22649097
        supporting_text: "the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including HDAC4, HDAC5, HDAC9, megalin, and regulatory factor X, 5 (RFX5)"

- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >
      IEA annotation for nuclear localization based on combined automated methods.
      This is consistent with experimental evidence showing nuclear localization.
    action: ACCEPT
    reason: >
      Nuclear localization is well-established for RFXANK as part of the nuclear
      RFX transcription regulatory complex.
    supported_by:
      - reference_id: PMID:10938133
        supporting_text: "the heterotrimeric transcription factor RFX (RFX-B, RFX5, and RFXAP)"

- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >
      IEA annotation for cytoplasmic localization. The RFX complex assembles in the
      cytoplasm before nuclear translocation, so cytoplasmic localization is expected.
    action: ACCEPT
    reason: >
      The RFX5-RFXAP subcomplex assembles in the cytoplasm prior to nuclear localization,
      consistent with cytoplasmic presence of RFXANK during complex assembly.
    supported_by:
      - reference_id: PMID:20732328
        supporting_text: "Two RFX5 molecules and one RFXAP molecule assemble in the cytoplasm prior to nuclear localization"

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:10938133
  review:
    summary: >
      This IPI annotation documents physical interaction between RFX complex components.
      However, GO:0005515 (protein binding) is too vague and uninformative.
    action: MODIFY
    reason: >
      While protein binding is demonstrated, GO:0005515 is not informative. RFXANK
      has specific roles as part of a transcription regulatory complex. The annotation
      should be converted to a more specific term reflecting its function.
    proposed_replacement_terms:
      - id: GO:0003713
        label: transcription coactivator activity
    supported_by:
      - reference_id: PMID:10938133
        supporting_text: "The results identified specific domains within each of the three RFX subunits that were necessary for RFX complex formation, including the ankyrin repeats of RFX-B."

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20211142
  review:
    summary: >
      IPI annotation for protein binding from a high-throughput interaction study.
      GO:0005515 is not informative about the nature of the interaction.
    action: KEEP_AS_NON_CORE
    reason: >
      This is a high-throughput study. The annotation documents physical interactions
      but GO:0005515 is too vague to be a core annotation.

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:25752541
  review:
    summary: >
      This study characterized the interaction between RFXANK ankyrin repeats and
      the PxLPxL motif in RFX7 and other proteins. While it documents specific
      protein-protein interactions, GO:0005515 is not informative.
    action: KEEP_AS_NON_CORE
    reason: >
      The study provides structural insight into RFXANK's ankyrin repeat-mediated
      interactions, but protein binding is not informative for a protein whose
      main function is mediated through protein-protein interactions as a coactivator.
    supported_by:
      - reference_id: PMID:25752541
        supporting_text: "Ankyrin repeats of ANKRA2 recognize a PxLPxL motif on the 3M syndrome protein CCDC8"

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:31864703
  review:
    summary: >
      IPI annotation for protein binding. GO:0005515 is not informative.
    action: KEEP_AS_NON_CORE
    reason: >
      Non-informative GO:0005515 annotation from interaction studies.

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:33961781
  review:
    summary: >
      IPI annotation from proteome-scale interactome study. GO:0005515 is not informative.
    action: KEEP_AS_NON_CORE
    reason: >
      High-throughput interactome data. GO:0005515 is too generic.

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:40205054
  review:
    summary: >
      IPI annotation from multimodal cell maps study. GO:0005515 is not informative.
    action: KEEP_AS_NON_CORE
    reason: >
      High-throughput interactome data. GO:0005515 is too generic for RFXANK's
      functionally important protein interactions.

- term:
    id: GO:0042826
    label: histone deacetylase binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: >
      This annotation is based on ortholog transfer from mouse. The interaction
      of RFXANK/ANKRA2 family proteins with HDACs is documented in the literature.
      RFXANK's ankyrin repeats recognize a PxLPxI/L motif found in HDAC4, HDAC5, and HDAC9.
    action: ACCEPT
    reason: >
      The related protein ANKRA2 (and by structural homology RFXANK) has been shown
      to bind class IIa HDACs via their PxLPxI/L motifs. This interaction is documented
      in PMID:22649097.
    supported_by:
      - reference_id: PMID:22649097
        supporting_text: "the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including HDAC4, HDAC5, HDAC9"

- term:
    id: GO:0005654
    label: nucleoplasm
  evidence_type: IDA
  original_reference_id: GO_REF:0000052
  review:
    summary: >
      IDA annotation for nucleoplasm localization based on immunofluorescence data
      from Human Protein Atlas. Consistent with nuclear function.
    action: ACCEPT
    reason: >
      Nucleoplasm localization is consistent with RFXANK's role in the RFX
      transcription regulatory complex.

- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:10938133
  review:
    summary: >
      IDA annotation for nuclear localization from experimental study of
      RFX complex components.
    action: ACCEPT
    reason: >
      Well-supported experimental evidence for nuclear localization.
    supported_by:
      - reference_id: PMID:10938133
        supporting_text: "Mutagenesis of the RFX genes was performed, and the properties of the proteins were analyzed with regard to transactivation, DNA binding, and protein-protein interactions."

- term:
    id: GO:0045348
    label: positive regulation of MHC class II biosynthetic process
  evidence_type: NAS
  original_reference_id: PMID:10938133
  review:
    summary: >
      This is the core biological function of RFXANK. The RFX complex is essential
      for MHC class II gene expression, and mutations in RFXANK cause MHC class II
      deficiency (bare lymphocyte syndrome).
    action: ACCEPT
    reason: >
      This is a well-established core function of RFXANK. Mutations in RFXANK abolish
      MHC class II expression, causing severe immunodeficiency.
    supported_by:
      - reference_id: PMID:9806546
        supporting_text: "RFXANK restores MHC-II expression in cell lines from patients in group B and is mutated in these patients"
      - reference_id: PMID:10938133
        supporting_text: "The bare lymphocyte syndrome, a severe combined immunodeficiency due to loss of major histocompatibility complex (MHC) class II gene expression, is caused by inherited mutations in the genes encoding the heterotrimeric transcription factor RFX (RFX-B, RFX5, and RFXAP)"

- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IDA
  original_reference_id: PMID:10938133
  review:
    summary: >
      IDA annotation for positive regulation of transcription. The RFX complex
      activates transcription of MHC class II genes.
    action: ACCEPT
    reason: >
      RFXANK is essential for RFX complex function in activating MHC class II
      gene transcription.
    supported_by:
      - reference_id: PMID:10938133
        supporting_text: "Mutagenesis of the RFX genes was performed, and the properties of the proteins were analyzed with regard to transactivation, DNA binding, and protein-protein interactions."

- term:
    id: GO:0000977
    label: RNA polymerase II transcription regulatory region sequence-specific DNA binding
  evidence_type: IDA
  original_reference_id: PMID:9806546
  review:
    summary: >
      This annotation uses the "contributes_to" qualifier (in GOA), indicating RFXANK contributes
      to the complex's DNA binding activity. However, RFXANK does NOT bind DNA directly.
      The DNA-binding component of the RFX complex is RFX5, which contains the DNA-binding
      domain that recognizes the X box motif. RFXANK's ankyrin repeats are protein-protein
      interaction domains that bind RFX5, not DNA. While the "contributes_to" qualifier
      acknowledges that RFXANK is not the direct DNA-binding subunit, this annotation
      is still misleading because it implies some direct involvement in DNA binding.
    action: REMOVE
    reason: >
      RFXANK does not bind DNA in any capacity. Its ankyrin repeats mediate protein-protein
      interactions with RFX5 and other partners. The RFX complex binds DNA through RFX5,
      not RFXANK. While RFXANK is required for proper complex assembly and function,
      this is mediated entirely through protein-protein interactions, not DNA binding.
      A "contributes_to" annotation for a DNA-binding term is inappropriate for a protein
      that has no DNA-binding activity whatsoever.
    supported_by:
      - reference_id: PMID:9806546
        supporting_text: "RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats. Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters."
      - reference_id: PMID:22649097
        supporting_text: "the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins"

- term:
    id: GO:0001228
    label: DNA-binding transcription activator activity, RNA polymerase II-specific
  evidence_type: IDA
  original_reference_id: PMID:9806546
  review:
    summary: >
      This annotation with "contributes_to" qualifier (in GOA) is INCORRECT and should be removed.
      GO:0001228 is defined as "A DNA-binding transcription factor activity that activates
      or increases transcription" - this explicitly requires DNA binding as part of the
      definition. RFXANK does NOT bind DNA. It contains ankyrin repeats (protein-protein
      interaction domains), not DNA-binding domains. The DNA-binding component of the
      RFX complex is RFX5, which binds the X box motif. RFXANK should be annotated as
      a transcription coactivator (GO:0003713), not as having DNA-binding transcription
      factor activity.
    action: MODIFY
    reason: >
      RFXANK is a transcription coactivator/coregulator, NOT a DNA-binding transcription
      factor. It functions by binding to RFX5 (the DNA-binding subunit) via its ankyrin
      repeats recognizing the PxLPxI/L motif. The "contributes_to" qualifier does not
      salvage this annotation because GO:0001228 inherently requires DNA binding as
      part of its definition. The appropriate molecular function term for RFXANK is
      GO:0003713 (transcription coactivator activity), which is defined as a transcription
      coregulator activity that activates transcription via binding to a DNA-binding
      transcription factor.
    proposed_replacement_terms:
      - id: GO:0003713
        label: transcription coactivator activity
    additional_reference_ids:
      - PMID:22649097
    supported_by:
      - reference_id: PMID:9806546
        supporting_text: "RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats. Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters."
      - reference_id: PMID:22649097
        supporting_text: "the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including HDAC4, HDAC5, HDAC9, megalin, and regulatory factor X, 5 (RFX5). Crystal structures of the ankyrin repeat domain of ANKRA2 in complex with its binding peptides revealed that each of the middle three ankyrin repeats of ANKRA2 recognizes a residue from the PxLPxI/L motif in a tumbler-lock binding mode"
      - reference_id: PMID:10938133
        supporting_text: "DNA binding was dependent on RFX complex formation, and transactivation was dependent on a region of RFX5."

- term:
    id: GO:0090575
    label: RNA polymerase II transcription regulator complex
  evidence_type: IPI
  original_reference_id: PMID:9806546
  review:
    summary: >
      RFXANK is part of the RFX transcription regulatory complex. This cellular
      component annotation is appropriate.
    action: ACCEPT
    reason: >
      RFXANK is one of the four subunits of the heterotetrameric RFX complex that
      regulates MHC class II transcription.
    supported_by:
      - reference_id: PMID:9806546
        supporting_text: "the identification of RFXANK, the gene encoding a third subunit of RFX"
      - reference_id: PMID:20732328
        supporting_text: "RFX comprises three proteins: RFX5 (two copies), RFXAP, and RFXB"

- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IDA
  original_reference_id: PMID:9806546
  review:
    summary: >
      IDA annotation for positive regulation of transcription based on the discovery
      paper. RFXANK restores MHC-II expression when introduced into patient cells.
      Deep research confirms RFXANK is essential for RFX complex function in activating
      MHC class II transcription [RFXANK-deep-research-falcon.md].
    action: ACCEPT
    reason: >
      Well-established experimental evidence that RFXANK is required for positive
      regulation of MHC class II gene transcription.
    supported_by:
      - reference_id: PMID:9806546
        supporting_text: "RFXANK restores MHC-II expression in cell lines from patients in group B"

# Proposed NEW annotations
- term:
    id: GO:0003713
    label: transcription coactivator activity
  evidence_type: IDA
  original_reference_id: PMID:9806546
  review:
    summary: >
      RFXANK functions as a transcription coactivator as part of the RFX complex.
      It activates transcription of MHC class II genes by binding to the DNA-binding
      transcription factor RFX5 (via its ankyrin repeats), enabling the assembly and
      function of the RFX complex on MHC class II promoters. This is the appropriate
      molecular function annotation for RFXANK's role in the RFX complex.
    action: NEW
    reason: >
      GO:0003713 (transcription coactivator activity) is defined as "A transcription
      coregulator activity that activates or increases the transcription of specific
      gene sets via binding to a DNA-binding transcription factor at a specific genomic
      locus, either on its own or as part of a complex." This precisely describes
      RFXANK's function: it activates MHC class II transcription by binding to RFX5
      (the DNA-binding transcription factor) as part of the RFX complex. This annotation
      should replace the incorrect GO:0001228 annotation.
    additional_reference_ids:
      - PMID:10938133
      - PMID:22649097
    supported_by:
      - reference_id: PMID:9806546
        supporting_text: "RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats. Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters."
      - reference_id: PMID:10938133
        supporting_text: "The results identified specific domains within each of the three RFX subunits that were necessary for RFX complex formation, including the ankyrin repeats of RFX-B. DNA binding was dependent on RFX complex formation, and transactivation was dependent on a region of RFX5."
      - reference_id: PMID:22649097
        supporting_text: "the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including... regulatory factor X, 5 (RFX5)"

references:
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000043
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
  findings: []
- id: GO_REF:0000052
  title: Gene Ontology annotation based on curation of immunofluorescence data
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to
    orthologs using Ensembl Compara
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:9806546
  title: A gene encoding a novel RFX-associated transactivator is mutated in the majority
    of MHC class II deficiency patients.
  findings:
    - statement: RFXANK is the third subunit of the RFX complex
      supporting_text: "the identification of RFXANK, the gene encoding a third subunit of RFX"
    - statement: RFXANK contains ankyrin repeats (protein-protein interaction domains)
      supporting_text: "RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats"
    - statement: RFXANK interaction with RFX5 and RFXAP is essential for RFX complex binding to MHC-II promoters
      supporting_text: "Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters"
    - statement: RFXANK mutations cause MHC class II deficiency (complementation group B)
      supporting_text: "RFXANK restores MHC-II expression in cell lines from patients in group B and is mutated in these patients"
- id: PMID:10938133
  title: Associations and interactions between bare lymphocyte syndrome factors.
  findings:
    - statement: The heterotrimeric RFX complex consists of RFX-B (RFXANK), RFX5, and RFXAP
      supporting_text: "The bare lymphocyte syndrome, a severe combined immunodeficiency due to loss of major histocompatibility complex (MHC) class II gene expression, is caused by inherited mutations in the genes encoding the heterotrimeric transcription factor RFX (RFX-B, RFX5, and RFXAP)"
    - statement: Ankyrin repeats of RFX-B are necessary for RFX complex formation
      supporting_text: "The results identified specific domains within each of the three RFX subunits that were necessary for RFX complex formation, including the ankyrin repeats of RFX-B"
    - statement: DNA binding is dependent on RFX complex formation
      supporting_text: "DNA binding was dependent on RFX complex formation"
    - statement: Transactivation is dependent on a region of RFX5
      supporting_text: "transactivation was dependent on a region of RFX5"
    - statement: RFX5 interacts with CIITA
      supporting_text: "RFX5 was found to interact with CIITA, and this interaction was dependent on a proline-rich domain within RFX5"
- id: PMID:20211142
  title: An atlas of combinatorial transcriptional regulation in mouse and man.
  findings: []
- id: PMID:20732328
  title: Solution structure of the heterotrimeric complex between the interaction
    domains of RFX5 and RFXAP from the RFX gene regulatory complex.
  findings:
    - statement: RFX comprises RFX5 (two copies), RFXAP, and RFXB (RFXANK)
      supporting_text: "RFX comprises three proteins: RFX5 (two copies), RFXAP, and RFXB"
    - statement: RFX5 and RFXAP assemble in cytoplasm prior to nuclear localization
      supporting_text: "Two RFX5 molecules and one RFXAP molecule assemble in the cytoplasm prior to nuclear localization"
    - statement: The RFX5-RFXAP complex binds RFXB with high affinity
      supporting_text: "the RFX5(N)(2)-RFXAP(C) complex binds RFXB with high affinity"
- id: PMID:22649097
  title: Sequence-specific recognition of a PxLPxI/L motif by an ankyrin repeat tumbler
    lock.
  findings:
    - statement: RFXANK ankyrin repeats recognize PxLPxI/L motif in RFX5
      supporting_text: "the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including... regulatory factor X, 5 (RFX5)"
    - statement: RFXANK also binds HDAC4, HDAC5, HDAC9 via their PxLPxI/L motifs
      supporting_text: "the ankyrin repeat domains of ANKRA2 and its close paralog regulatory factor X-associated ankyrin-containing protein (RFXANK) recognize a PxLPxI/L motif found in diverse binding proteins, including HDAC4, HDAC5, HDAC9"
    - statement: Disease-causing mutations in RFXANK affect residues critical for RFX5 binding
      supporting_text: "three disease-causing mutations in RFXANK affect residues that are critical for binding to RFX5"
    - statement: Crystal structure reveals tumbler-lock binding mode
      supporting_text: "Crystal structures of the ankyrin repeat domain of ANKRA2 in complex with its binding peptides revealed that each of the middle three ankyrin repeats of ANKRA2 recognizes a residue from the PxLPxI/L motif in a tumbler-lock binding mode"
- id: PMID:25752541
  title: Ankyrin repeats of ANKRA2 recognize a PxLPxL motif on the 3M syndrome protein
    CCDC8.
  findings:
    - statement: RFXANK interacts with RFX7 via its ankyrin repeats
      supporting_text: "ankyrin repeats of ANKRA2 and the paralogous bare lymphocyte syndrome transcription factor RFXANK recognize PxLPxL/I motifs... suggest novel regulatory mechanisms for histone deacetylases and RFX7"
- id: PMID:31864703
  title: Structural basis for the recognition of RFX7 by ANKRA2 and RFXANK.
  findings: []
- id: PMID:33961781
  title: Dual proteome-scale networks reveal cell-specific remodeling of the human
    interactome.
  findings: []
- id: PMID:40205054
  title: Multimodal cell maps as a foundation for structural and functional genomics.
  findings: []

core_functions:
  - description: >
      RFXANK functions as a transcription coactivator in the RFX complex. It binds
      to RFX5 (the DNA-binding subunit) via its ankyrin repeats, enabling assembly
      of the heterotetrameric RFX complex that activates MHC class II gene transcription.
    molecular_function:
      id: GO:0003713
      label: transcription coactivator activity
    directly_involved_in:
      - id: GO:0045348
        label: positive regulation of MHC class II biosynthetic process
    locations:
      - id: GO:0005634
        label: nucleus

proposed_new_terms: []

suggested_questions:
  - question: >
      Should RFXAP also be reclassified as a transcription coactivator rather than
      having DNA-binding transcription factor annotations? The same logic applies -
      RFXAP does not bind DNA directly.
  - question: >
      Are the GO annotations for RFX5 appropriately capturing its role as the DNA-binding
      subunit of the RFX complex?
  - question: >
      Should there be a specific GO term for "regulatory subunit of transcription factor complex"
      to better capture the roles of proteins like RFXANK and RFXAP?

suggested_experiments:
  - description: >
      ChIP-seq comparing RFX5 binding with and without RFXANK to definitively demonstrate
      that RFXANK does not contribute to DNA binding specificity.
    hypothesis: RFXANK does not contribute directly to DNA binding specificity
  - description: >
      EMSA experiments testing purified RFXANK alone vs. RFX5 alone vs. complete RFX complex
      to demonstrate that only RFX5-containing complexes bind DNA.
    hypothesis: Only RFX5 provides DNA-binding activity to the RFX complex

Gene Description

Existing Annotations Review

Core Functions

RFXANK functions as a transcription coactivator in the RFX complex. It binds to RFX5 (the DNA-binding subunit) via its ankyrin repeats, enabling assembly of the heterotetrameric RFX complex that activates MHC class II gene transcription.

References

Suggested Questions for Experts

Suggested Experiments

Deep Research

Falcon

Citations

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