PDCD5

UniProt ID: O14737
Organism: Homo sapiens
Review Status: COMPLETE
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Gene Description

PDCD5 (Programmed cell death protein 5, also known as TFAR19) is a pro-apoptotic regulatory adaptor protein that functions primarily as a positive regulator of the p53/TP53 tumor suppressor pathway. Under normal conditions, PDCD5 helps maintain basal levels of p53 and Tip60 (a histone acetyltransferase). Upon DNA damage or genotoxic stress, PDCD5 is phosphorylated at Ser-119 by CK2, which stabilizes the protein and promotes its translocation from cytosol to nucleus. In the nucleus, PDCD5 performs two key functions: (1) it binds to and activates Tip60, enhancing its HAT activity and Tip60-dependent K120 acetylation of p53; (2) it directly binds p53 and antagonizes MDM2-mediated p53 ubiquitination and degradation, thereby stabilizing p53 and promoting p53-dependent transcription of pro-apoptotic genes (BAX, PUMA). PDCD5 is also regulated by OTUD5 (deubiquitinase that stabilizes it) and JMJD4/PPEF-1 (which promote its degradation). Beyond apoptosis, PDCD5 interacts with FOXP3 to enhance Treg function and suppress autoimmunity. It also inhibits beta-tubulin folding by binding to the CCT chaperonin complex, which may contribute to its anti-proliferative effects.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0005634 nucleus
IBA
GO_REF:0000033 		ACCEPT
Summary: PDCD5 nuclear localization is well-documented and represents a key functional location, particularly during genotoxic stress responses. Multiple primary studies demonstrate nuclear localization by immunofluorescence and fractionation [PMID:19308289, PMID:22914926, PMID:28051100, PMID:24012345]. The IBA annotation is consistent with phylogenetic conservation and experimental data.
Reason: Nuclear localization is essential for PDCD5 function in p53 activation and DNA damage response. CK2-mediated phosphorylation at Ser-119 promotes nuclear translocation during genotoxic stress [PMID:28051100].
Supporting Evidence:
PMID:28051100
PDCD5 phosphorylation at Ser-119 is rapidly induced by the genotoxic stress response, which stabilizes the protein and results in PDCD5 nuclear translocation
PMID:19308289
PDCD5 levels increase significantly on DNA damage in U2OS cells
GO:0005829 cytosol
IBA
GO_REF:0000033 		ACCEPT
Summary: PDCD5 is found in the cytosol under basal conditions and translocates to the nucleus upon DNA damage or genotoxic stress. The cytosolic localization represents its resting state location [PMID:28051100]. This dual localization is consistent with its function as a stress-responsive signaling molecule.
Reason: Cytosolic localization is the default location for PDCD5 in unstressed cells. Upon phosphorylation at Ser-119, PDCD5 translocates to the nucleus for its pro-apoptotic function.
Supporting Evidence:
PMID:28051100
PDCD5 phosphorylation is maintained at a low level in the absence of genotoxic stress
GO:0003677 DNA binding
IEA
GO_REF:0000002 		UNDECIDED
Summary: This annotation is derived from InterPro domain mapping (PDCD5-like domain, dsDNA_bind PF01984). While the structural similarity suggests potential DNA binding capability, there is limited direct experimental evidence for PDCD5 DNA binding activity in primary literature. The deep research report notes that "Structural and domain annotations... were not retrievable within the 2023-2024 sources."
Reason: The annotation is based on domain homology but lacks direct experimental validation. PDCD5 functions primarily through protein-protein interactions (with Tip60, p53, MDM2, FOXP3, CCT) rather than direct DNA binding. The ChIP experiment in PMID:22914926 shows PDCD5 association at the p21 promoter, but this may be indirect through p53 binding rather than direct DNA binding.
GO:0005515 protein binding
IPI
PMID:19308289
PDCD5 interacts with Tip60 and functions as a cooperator in ... 		MODIFY
Summary: This annotation indicates PDCD5 binds to Tip60 (Q92993). PMID:19308289 demonstrates that "PDCD5 binds to Tip60 and enhances the stability of Tip60 protein" and "The binding amount of PDCD5 and Tip60 is significantly increased after UV irradiation."
Reason: While the interaction with Tip60 is valid and experimentally demonstrated, the generic 'protein binding' term is uninformative. PDCD5 functions as a Tip60 coactivator, enhancing its acetyltransferase activity. A more specific term should be used.
Supporting Evidence:
PMID:19308289
PDCD5 enhances HAT activity of Tip60 and Tip60-dependent histone acetylation in both basal and UV-induced levels
GO:0005634 nucleus
IDA
PMID:19308289
PDCD5 interacts with Tip60 and functions as a cooperator in ... 		ACCEPT
Summary: Direct experimental evidence from PMID:19308289 showing nuclear localization. The study demonstrates co-localization with Tip60 in the nucleus and increased nuclear PDCD5 after DNA damage.
Reason: Primary experimental data demonstrating nuclear localization. This is consistent with PDCD5's function in the p53 pathway and DNA damage response.
Supporting Evidence:
PMID:19308289
PDCD5 levels increase significantly on DNA damage in U2OS cells, as does Tip60
GO:0006915 apoptotic process
IEA
GO_REF:0000043 		MODIFY
Summary: This annotation is derived from the UniProt keyword "Apoptosis" (KW-0053). PDCD5 is indeed involved in apoptosis, as extensively documented in primary literature. It was originally cloned as an apoptosis-related gene [PMID:9920759] and promotes apoptosis through the p53/Tip60 pathway [PMID:19308289, PMID:22914926].
Reason: The annotation is correct but too general. PDCD5 specifically promotes apoptosis rather than just being "involved in" it. The more specific term GO:0043065 (positive regulation of apoptotic process) or GO:1902255 (positive regulation of intrinsic apoptotic signaling pathway by p53 class mediator) better captures its function.
GO:0140311 protein sequestering activity
IDA
PMID:19308289
PDCD5 interacts with Tip60 and functions as a cooperator in ... 		ACCEPT
Summary: This annotation relates to PDCD5's function in sequestering proteins. According to PMID:19308289, PDCD5 binds Tip60 and stabilizes it. From PMID:22914926, PDCD5 binds p53 and antagonizes MDM2-mediated p53 degradation by "dissociating the interaction between p53 and Mdm2."
Reason: PDCD5 does function to sequester/stabilize binding partners (Tip60, p53) away from degradation pathways. It prevents MDM2 from binding p53 by directly interacting with both proteins.
Supporting Evidence:
PMID:22914926
PDCD5 could dissociate the interaction between p53 and Mdm2 and interact with Mdm2 directly to promote its degradation
GO:1901798 positive regulation of signal transduction by p53 class mediator
IMP
PMID:19308289
PDCD5 interacts with Tip60 and functions as a cooperator in ... 		ACCEPT
Summary: PMID:19308289 demonstrates that PDCD5 enhances p53 signaling through Tip60-mediated K120 acetylation of p53 and participates in p53-dependent expression of pro-apoptotic genes like Bax. Knockdown of PDCD5 impairs p53-dependent apoptosis.
Reason: This represents a core function of PDCD5. The protein positively regulates p53 signaling at multiple levels: stabilizing p53 protein, enhancing p53 acetylation via Tip60, and promoting p53-dependent gene transcription.
Supporting Evidence:
PMID:19308289
PDCD5 increases Tip60-dependent K120 acetylation of p53 and participates in the p53-dependent expression of apoptosis-related genes, such as Bax
GO:0005515 protein binding
IPI
PMID:32296183
A reference map of the human binary protein interactome. 		MARK AS OVER ANNOTATED
Summary: This annotation is from high-throughput binary protein interactome mapping (HuRI). The interacting partners listed include PICK1 (Q9NRD5), RAD18 (Q9NS91), and TRIM35 (Q9UPQ4-2). These are from a systematic screen rather than hypothesis-driven studies.
Reason: High-throughput interactome studies often identify many interactions. While these interactions may be real, the generic 'protein binding' term provides no functional insight. The biological significance of PDCD5 interactions with PICK1, RAD18, or TRIM35 has not been characterized in follow-up studies.
GO:0005634 nucleus
IDA
PMID:22914926
PDCD5 interacts with p53 and functions as a positive regulat... 		ACCEPT
Summary: PMID:22914926 confirms nuclear localization through co-localization assays and shows PDCD5 associates with p53 at the p21 promoter by ChIP. This study provides independent confirmation of nuclear localization.
Reason: Multiple lines of evidence confirm nuclear localization. This study adds ChIP data showing PDCD5 at chromatin in the nucleus.
Supporting Evidence:
PMID:22914926
chromatin immunoprecipitation assays showed an up-regulated association of PDCD5 at the p53BS2 site of the p21 promoter during DNA damage
GO:0005634 nucleus
IDA
PMID:28051100
Protein serine/threonine phosphatase PPEF-1 suppresses genot... 		ACCEPT
Summary: PMID:28051100 demonstrates nuclear localization by immunofluorescence and shows that phosphorylation at Ser-119 promotes nuclear translocation. PPEF-1 dephosphorylates PDCD5 and prevents nuclear accumulation.
Reason: This study provides mechanistic insight into how PDCD5 nuclear localization is regulated by phosphorylation status.
Supporting Evidence:
PMID:28051100
ET treatment rapidly induced nuclear accumulation of PDCD5... Wild-type PPEF-1 completely abrogated PDCD5 stabilization in response to ET
GO:0042110 T cell activation
IPI
PMID:24012345
PDCD5 negatively regulates autoimmunity by upregulating FOXP... 		MODIFY
Summary: PMID:24012345 shows PDCD5 interacts with FOXP3 (Q9BZS1) in T cells. The study demonstrates that PDCD5 enhances FOXP3 function, increases Treg cell frequency, and suppresses Th17/Th1 responses. However, the annotation suggests PDCD5 promotes T cell activation, which is the opposite of what the paper shows.
Reason: The annotation is misleading. PDCD5 does not promote T cell activation but rather suppresses it by enhancing regulatory T cell (Treg) function and inhibiting effector T cell responses. A term related to Treg regulation would be more appropriate.
Supporting Evidence:
PMID:24012345
PDCD5 negatively regulates autoimmunity by upregulating FOXP3(+) regulatory T cells and suppressing Th17 and Th1 responses
GO:0140311 protein sequestering activity
IDA
PMID:22914926
PDCD5 interacts with p53 and functions as a positive regulat... 		ACCEPT
Summary: PMID:22914926 demonstrates that PDCD5 binds p53 and sequesters it from MDM2-mediated degradation. PDCD5 also directly interacts with MDM2 to promote its degradation.
Reason: Protein sequestering activity accurately describes PDCD5's mechanism of protecting p53 from MDM2.
Supporting Evidence:
PMID:22914926
PDCD5 enhanced the stability of p53 by antagonizing Mdm2-induced p53 ubiquitination, nuclear export and proteasomal degradation
GO:1901798 positive regulation of signal transduction by p53 class mediator
IMP
PMID:22914926
PDCD5 interacts with p53 and functions as a positive regulat... 		ACCEPT
Summary: PMID:22914926 provides extensive IMP evidence for PDCD5 positive regulation of p53 signaling. Knockdown of PDCD5 decreases p53 phosphorylation and p21 expression, while PDCD5 is required for G1 arrest during DNA damage.
Reason: Core function of PDCD5. This study provides complementary evidence to PMID:19308289.
Supporting Evidence:
PMID:22914926
knockdown of PDCD5 by RNA interference decreased the p53 phosphorylation at Ser9, 20 and 392 residues, as well as the expression of p21 protein
GO:1902255 positive regulation of intrinsic apoptotic signaling pathway by p53 class mediator
ISS
GO_REF:0000024 		ACCEPT
Summary: This ISS annotation is transferred from mouse PDCD5 (UniProtKB:P56812) based on sequence similarity. The term is highly specific and consistent with PDCD5's function in promoting p53-mediated apoptosis through the intrinsic (mitochondrial) pathway.
Reason: The annotation is consistent with PDCD5's established function. PMID:16374546 shows PDCD5 is involved in cytochrome c release and Bax translocation to mitochondria, which are hallmarks of the intrinsic apoptotic pathway.
Supporting Evidence:
PMID:16374546
Suppressed expression of PDCD5 attenuates the release of cytochrome c from mitochondria to cytosol induced by Bax overexpression
GO:0042981 regulation of apoptotic process
IMP
PMID:16374546
Short interfering RNA against the PDCD5 attenuates cell apop... 		MODIFY
Summary: PMID:16374546 demonstrates that siRNA knockdown of PDCD5 attenuates apoptosis and caspase-3 activity induced by Bax overexpression. The paper shows PDCD5 modulates Bax translocation and cytochrome c release.
Reason: While accurate, this term is less specific than the evidence supports. PDCD5 specifically promotes apoptosis (positive regulation), not merely regulates it in an unspecified direction.
Supporting Evidence:
PMID:16374546
The programmed cell death 5 (PDCD5) protein plays an important apoptosis-accelerating role in cells undergoing apoptosis
GO:0005737 cytoplasm
HDA
PMID:16791210
Dynamic proteomics in individual human cells uncovers widesp... 		ACCEPT
Summary: This high-throughput localization study (PMID:16791210) used YFP-tagged proteins to systematically study nuclear protein dynamics. The detection of PDCD5 in cytoplasm is consistent with its known cytosol-to-nucleus translocation pattern.
Reason: While HDA evidence is lower quality than IDA, the cytoplasmic localization is consistent with extensive literature showing PDCD5 in cytosol under basal conditions.
Supporting Evidence:
PMID:28051100
PDCD5 protein is maintained at a low level in the absence of genotoxic stress response
GO:0010698 acetyltransferase activator activity
IDA
PMID:24012345
PDCD5 negatively regulates autoimmunity by upregulating FOXP... 		ACCEPT
Summary: PMID:24012345 shows PDCD5 "increases acetylation of FOXP3 in synergy with Tip60." This is consistent with earlier work (PMID:19308289) showing PDCD5 enhances Tip60 HAT activity. PDCD5 acts as a coactivator for Tip60-mediated acetylation.
Reason: Core molecular function of PDCD5. It enhances the acetyltransferase activity of Tip60 on multiple substrates including p53 and FOXP3.
Supporting Evidence:
PMID:24012345
PDCD5 interacts with FOXP3, increases acetylation of FOXP3 in synergy with Tip60
PMID:19308289
PDCD5 enhances HAT activity of Tip60
GO:0071560 cellular response to transforming growth factor beta stimulus
IDA
PMID:24012345
PDCD5 negatively regulates autoimmunity by upregulating FOXP... 		KEEP AS NON CORE
Summary: PMID:24012345 demonstrates that naive CD4+ T cells from PDCD5 transgenic mice are "more sensitive to TGF-beta-induced Treg polarization and expansion." This indicates PDCD5 modulates the cellular response to TGF-beta.
Reason: This is a genuine function but represents a context-specific role in T cells rather than the core molecular function of PDCD5 (which is p53/Tip60 pathway regulation). The TGF-beta response relates to PDCD5's role in Treg differentiation.
Supporting Evidence:
PMID:24012345
NaΓ―ve CD4(+) T cells from PDCD5tg mice were more sensitive to TGF-Ξ²-induced Treg polarization and expansion
GO:0005515 protein binding
IPI
PMID:24012345
PDCD5 negatively regulates autoimmunity by upregulating FOXP... 		MODIFY
Summary: This annotation indicates PDCD5 binds FOXP3 (Q9BZS1). PMID:24012345 demonstrates that "PDCD5 interacts with FOXP3" through biochemical assays.
Reason: The generic 'protein binding' term is uninformative. PDCD5 functions as a FOXP3 coactivator, enhancing FOXP3 acetylation and stability. A more specific functional term should be used.
Supporting Evidence:
PMID:24012345
PDCD5 interacts with FOXP3, increases acetylation of FOXP3 in synergy with Tip60 and enhances the repressive function of FOXP3
GO:0005634 nucleus
IDA
PMID:24012345
PDCD5 negatively regulates autoimmunity by upregulating FOXP... 		ACCEPT
Summary: Another independent IDA confirmation of nuclear localization from PMID:24012345.
Reason: Multiple IDA annotations for nuclear localization from different labs confirm this is a well-established location for PDCD5 function.
GO:0048487 beta-tubulin binding
IPI
PMID:24375412
Programmed cell death protein 5 interacts with the cytosolic... 		ACCEPT
Summary: PMID:24375412 demonstrates that "PDCD5 formed a complex with CCT and beta-tubulin" and specifically inhibits beta-tubulin folding. The interaction was mapped by cryo-EM to the CCTbeta apical domain.
Reason: The beta-tubulin binding is experimentally validated and functionally significant. It provides a mechanism for PDCD5's anti-proliferative effects through inhibition of tubulin folding.
Supporting Evidence:
PMID:24375412
PDCD5 formed a complex with CCT and beta-tubulin, a key CCT-folding substrate, and specifically inhibited beta-tubulin folding
GO:1903333 negative regulation of protein folding
IMP
PMID:24375412
Programmed cell death protein 5 interacts with the cytosolic... 		KEEP AS NON CORE
Summary: PMID:24375412 shows PDCD5 inhibits beta-tubulin folding by binding to the CCT chaperonin and sterically interfering with substrate access.
Reason: This is a validated function but represents a distinct mechanism from PDCD5's primary role in p53/Tip60 pathway regulation. It may contribute to PDCD5's anti-proliferative effects but is not its core function in apoptosis.
Supporting Evidence:
PMID:24375412
PDCD5 might exert its apoptotic function at least in part through inhibition of beta-tubulin folding
GO:0005515 protein binding
IPI
PMID:24375412
Programmed cell death protein 5 interacts with the cytosolic... 		MODIFY
Summary: This annotation indicates PDCD5 binds CCT5/TCP-1 epsilon (P48643). The interaction was characterized by proteomics and cryo-EM.
Reason: Generic 'protein binding' is uninformative. The interaction with CCT has a specific functional consequence (inhibition of beta-tubulin folding).
Proposed replacements: chaperone binding
Supporting Evidence:
PMID:24375412
A proteomics search for binding partners of phosducin-like protein, a co-chaperone for the cytosolic chaperonin containing tailless complex polypeptide 1 (CCT), revealed a robust interaction between PDCD5 and CCT
GO:0008201 heparin binding
IDA
PMID:17165023
Studies on interactions of programmed cell death 5 (PDCD5) a... 		MARK AS OVER ANNOTATED
Summary: PMID:17165023 uses capillary zone electrophoresis to demonstrate PDCD5-heparin interaction with a binding constant of 4.17 x 10^4 M^-1. However, the biological significance of this interaction is unclear.
Reason: While the biochemical interaction is documented, the physiological relevance of PDCD5 binding to heparin is not established. This appears to be an in vitro finding without clear in vivo significance. The paper is primarily a methods paper for CZE analysis.
Supporting Evidence:
PMID:17165023
The binding constant of the interaction between PDCD5 and heparin was calculated as 4.17 x 10(4) M(-1) by Scatchard analysis
GO:0070062 extracellular exosome
HDA
PMID:20458337
MHC class II-associated proteins in B-cell exosomes and pote... 		KEEP AS NON CORE
Summary: High-throughput detection of PDCD5 in B-cell exosomes. The biological significance of exosomal PDCD5 is not characterized.
Reason: While the localization in exosomes may be real (HDA evidence from proteomics), this does not represent a functional location for PDCD5's characterized activities. It may represent secretion/clearance rather than active function.
GO:0043065 positive regulation of apoptotic process
IMP
PMID:9920759
TFAR19, a novel apoptosis-related gene cloned from human leu... 		ACCEPT
Summary: This is the original paper identifying PDCD5 (TFAR19). It shows overexpression of PDCD5 "enhances apoptosis triggered by growth factor or serum deprivation" in tumor cells. This established PDCD5 as a pro-apoptotic factor.
Reason: This is the foundational paper for PDCD5 function. Positive regulation of apoptosis is the core function of PDCD5, extensively validated by subsequent studies.
Supporting Evidence:
PMID:9920759
Overexpression of TFAR19 in tumor cells enhances apoptosis triggered by growth factor or serum deprivation

Core Functions

PDCD5 promotes apoptosis through multiple mechanisms: enhancing Tip60 HAT activity, stabilizing p53 by antagonizing MDM2, and promoting cytochrome c release. This is the primary function for which PDCD5 was discovered and named.

Molecular Function:
acetyltransferase activator activity
Directly Involved In:
positive regulation of apoptotic process positive regulation of signal transduction by p53 class mediator
Cellular Locations:
nucleus cytosol

PDCD5 sequesters p53 from MDM2-mediated degradation by directly binding both proteins and disrupting the MDM2-p53 interaction, thereby stabilizing p53 protein levels.

Molecular Function:
protein sequestering activity
Directly Involved In:
positive regulation of signal transduction by p53 class mediator
Cellular Locations:
nucleus

References

GO_REF:0000002
Gene Ontology annotation through association of InterPro records with GO terms
GO_REF:0000024
Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
GO_REF:0000033
Annotation inferences using phylogenetic trees
GO_REF:0000043
Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
PMID:9920759
TFAR19, a novel apoptosis-related gene cloned from human leukemia cell line TF-1, could enhance apoptosis of some tumor cells induced by growth factor withdrawal.
  • Original identification of PDCD5/TFAR19 as pro-apoptotic factor
PMID:16374546
Short interfering RNA against the PDCD5 attenuates cell apoptosis and caspase-3 activity induced by Bax overexpression.
  • PDCD5 knockdown reduces apoptosis
  • PDCD5 modulates Bax translocation and cytochrome c release
PMID:16791210
Dynamic proteomics in individual human cells uncovers widespread cell-cycle dependence of nuclear proteins.
  • High-throughput proteomics detecting PDCD5 localization
PMID:17165023
Studies on interactions of programmed cell death 5 (PDCD5) and its related peptides with heparin by capillary zone electrophoresis.
  • In vitro heparin binding demonstrated
PMID:19308289
PDCD5 interacts with Tip60 and functions as a cooperator in acetyltransferase activity and DNA damage-induced apoptosis.
  • PDCD5 binds and stabilizes Tip60
  • PDCD5 enhances Tip60 HAT activity
  • PDCD5 promotes p53 K120 acetylation via Tip60
  • Nuclear localization after DNA damage
PMID:20458337
MHC class II-associated proteins in B-cell exosomes and potential functional implications for exosome biogenesis.
  • PDCD5 detected in B-cell exosomes
PMID:22914926
PDCD5 interacts with p53 and functions as a positive regulator in the p53 pathway.
  • PDCD5 directly binds p53
  • PDCD5 antagonizes MDM2-mediated p53 degradation
  • PDCD5 promotes p53 phosphorylation
  • ChIP shows PDCD5 at p21 promoter
PMID:24012345
PDCD5 negatively regulates autoimmunity by upregulating FOXP3(+) regulatory T cells and suppressing Th17 and Th1 responses.
  • PDCD5 interacts with FOXP3
  • PDCD5 enhances FOXP3 acetylation with Tip60
  • PDCD5 promotes Treg differentiation
  • TGF-beta sensitivity enhanced in PDCD5 transgenic mice
PMID:24375412
Programmed cell death protein 5 interacts with the cytosolic chaperonin containing tailless complex polypeptide 1 (CCT) to regulate Ξ²-tubulin folding.
  • PDCD5 binds CCT chaperonin
  • PDCD5 inhibits beta-tubulin folding
  • Cryo-EM structure of PDCD5-CCT complex
PMID:28051100
Protein serine/threonine phosphatase PPEF-1 suppresses genotoxic stress response via dephosphorylation of PDCD5.
  • PPEF-1 dephosphorylates PDCD5 at Ser-119
  • Phosphorylation promotes nuclear localization
  • CK2 phosphorylates, PPEF-1 dephosphorylates
PMID:32296183
A reference map of the human binary protein interactome.
  • High-throughput interactome data

Suggested Questions for Experts

Q: What is the structural basis for PDCD5's dual functions in Tip60 activation and CCT inhibition?

Q: Is the heparin binding activity physiologically relevant?

Q: What determines whether PDCD5 promotes p53 stabilization vs. its role in Treg function?

Suggested Experiments

Experiment: ChIP-seq for PDCD5 to determine genome-wide chromatin binding. This would clarify whether PDCD5 has DNA binding activity or only associates with chromatin indirectly through p53.

Hypothesis: PDCD5 associates with chromatin indirectly through p53 rather than via direct DNA binding.

Experiment: Structural studies of PDCD5-Tip60 complex to reveal the molecular mechanism of Tip60 activation by PDCD5.

Hypothesis: PDCD5 binding to Tip60 induces conformational changes that enhance HAT activity.

Deep Research

Falcon

(PDCD5-deep-research-falcon.md)
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate. Falcon Edison Scientific Literature 16 citations 2026-02-08T20:33:05.172960

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
- Objective 1 (verification): Completed. The literature cited below explicitly studies human PDCD5/TFAR19 and its role in TP53 signaling, matching the provided UniProt identity and organism. (kim2024jmjd4promotestumor pages 1-2, kim2024jmjd4promotestumor pages 6-6)
- Objective 2 (recent sources) through Objective 6 (synthesis): Completed using 2023–2024 primary and clinical studies and one 2023 mechanistic review relevant to PDCD5 regulation and disease associations. (kim2024jmjd4promotestumor pages 1-2, fu2023theregulationand pages 6-8, peng2023dihydroartemisininenhancesthe pages 14-16, kim2024jmjd4promotestumor pages 2-3, fu2023theregulationand pages 4-6, kim2024jmjd4promotestumor pages 3-5, xiao2023pdcd5asa pages 1-2, xiao2023pdcd5asa pages 6-8, xiao2023pdcd5asa pages 12-14, xiao2023pdcd5asa pages 14-15)

Comprehensive research report: Human PDCD5 (TFAR19; UniProt O14737)

1) Key concepts and current definitions
- Identity and nomenclature: Programmed cell death protein 5 (PDCD5), also known as TFAR19, is a human protein broadly implicated in regulation of apoptosis and stress responses. 2024 mechanistic work explicitly uses human PDCD5/TFAR19 nomenclature and places PDCD5 upstream of TP53-mediated apoptosis, supporting the identity provided. URL: https://doi.org/10.5483/bmbrep.2024-0027 (published July 2024). (kim2024jmjd4promotestumor pages 1-2, kim2024jmjd4promotestumor pages 6-6)
- Core functional concept: PDCD5 promotes TP53 (p53) tumor-suppressor activity during genotoxic stress by stabilizing TP53 signaling outputs and enhancing expression of pro-apoptotic targets (e.g., BAX, PUMA). Mechanistically, PDCD5 levels and localization are dynamically regulated after DNA damage. URL: https://doi.org/10.5483/bmbrep.2024-0027 (2024); https://doi.org/10.3390/cells12081161 (2023). (kim2024jmjd4promotestumor pages 2-3, fu2023theregulationand pages 4-6)
- Subcellular localization dynamics: PDCD5 undergoes cytoplasm-to-nucleus translocation during apoptosis; nuclear PDCD5 has been described as an early apoptotic signal. In colon cancer models, dihydroartemisinin (DHA) triggers changes in PDCD5 subcellular distribution detectable by immunocytochemistry and fractionation. URL: https://doi.org/10.5483/bmbrep.2024-0027 (2024); https://doi.org/10.21203/rs.3.rs-3353635/v1 (preprint posted Sept 2023). (kim2024jmjd4promotestumor pages 6-6, peng2023dihydroartemisininenhancesthe pages 14-16)

2) Recent developments and latest research (2023–2024)
- JMJD4 as a negative regulator of PDCD5 (2024): Kim et al. identified JMJD4 as a direct PDCD5-binding protein by LC–MS, mapped the interaction (PDCD5 aa 91–125; JMJD4 aa 180–221), and showed JMJD4 lowers PDCD5 protein levels post-transcriptionally via proteasome-dependent degradation. JMJD4 overexpression reduced TP53, BAX, and PUMA under genotoxic stress, promoting proliferation and chemoresistance; JMJD4 knockdown had opposite effects. Clinical datasets linked high JMJD4 to poorer survival in colon and lung cancer. URL: https://doi.org/10.5483/bmbrep.2024-0027 (July 2024). (kim2024jmjd4promotestumor pages 1-2, kim2024jmjd4promotestumor pages 2-3, kim2024jmjd4promotestumor pages 3-5)
- OTUD5 as a positive regulator of PDCD5 stability (2023 review synthesizing primary studies): Under genotoxic stress, the deubiquitinase OTUD5 binds and deubiquitinates PDCD5, stabilizing it and enabling sequential activation of PDCD5 and TP53. OTUD5 depletion reduces PDCD5 and TP53 activation and confers resistance to chemotherapeutics in NSCLC models; overexpression has the inverse effect. URL: https://doi.org/10.3390/cells12081161 (April 2023). (fu2023theregulationand pages 6-8, fu2023theregulationand pages 4-6)
- PDCD5/ARAF axis in colon cancer and drug response (2023 preprint): In patient tissues (n=14) and cell/xenograft models, PDCD5 was lower in tumors versus adjacent tissues, suppressed proliferation and tumorigenicity, and enhanced oxaliplatin cytotoxicity. DHA increased PDCD5 nuclear localization and suppressed ARAF/MEK/ERK signaling, improving oxaliplatin effects via a PDCD5-dependent mechanism. URL: https://doi.org/10.21203/rs.3.rs-3353635/v1 (Sept 2023). (peng2023dihydroartemisininenhancesthe pages 14-16)

3) Functions, pathways, and localization in cellular context
- TP53 signaling and apoptosis: PDCD5 enhances TP53-mediated apoptosis under DNA-damage stress, increasing pro-apoptotic targets (e.g., BAX, PUMA) while lowering anti-apoptotic programs. Regulation of PDCD5 protein stability is central: OTUD5 deubiquitinates/stabilizes PDCD5, while JMJD4 promotes its proteasomal degradation. These opposing controls position PDCD5 as a convergence node integrating ubiquitin signaling with TP53-dependent apoptosis. URLs: 2024 BMB Reports https://doi.org/10.5483/bmbrep.2024-0027; 2023 Cells review https://doi.org/10.3390/cells12081161. (kim2024jmjd4promotestumor pages 1-2, kim2024jmjd4promotestumor pages 2-3, fu2023theregulationand pages 4-6)
- Nuclear translocation and site-of-action: During apoptosis or under certain therapeutic cues (e.g., DHA), PDCD5 accumulates in the nucleus, consistent with a role in chromatin- and transcription-coupled death programs. This nuclear localization is experimentally demonstrated by imaging and biochemical fractionation in colon cancer cells treated with DHA. URL: https://doi.org/10.21203/rs.3.rs-3353635/v1 (2023). (peng2023dihydroartemisininenhancesthe pages 14-16)
- Additional pathway links (colon cancer context): PDCD5 negatively influences ARAF/MEK/ERK signaling; functional rescue experiments indicate PDCD5-dependent suppression of ARAF contributes to anti-proliferative and chemosensitizing effects. URL: https://doi.org/10.21203/rs.3.rs-3353635/v1 (2023). (peng2023dihydroartemisininenhancesthe pages 14-16)

4) Disease associations, biomarkers, and real-world implementations
- Rheumatoid arthritis (RA) biomarker (2023 clinical study): In 152 newly diagnosed RA patients and 38 healthy controls, PDCD5 expression in blood was higher in active RA than in remission or controls. PDCD5 predicted remission with AUC 0.846 (95% CI 0.780–0.912); specificity 88.1%, sensitivity 86.6%. Higher PDCD5 associated with increased incidence risk (OR 1.73, 95% CI 1.45–1.98, P=0.005); a high-risk PDCD5 group had 2.94-fold greater incidence risk (95% CI 2.35–4.62, P<0.001). PDCD5 correlated with FOXP3, TNF-Ξ±, IL-17A, IFN-Ξ³, IL-6, and clinical indices (IgG, RF, CRP, ESR, anti-CCP, DAS28). These data support PDCD5 as a candidate blood biomarker to stratify RA disease activity and remission probability. URL: https://doi.org/10.1007/s40744-023-00587-5 (Aug 2023). (xiao2023pdcd5asa pages 1-2, xiao2023pdcd5asa pages 6-8, xiao2023pdcd5asa pages 12-14, xiao2023pdcd5asa pages 14-15)
- Oncology relevance (2023–2024): PDCD5 levels are frequently reduced in tumors, and its forced downregulation by JMJD4 promotes proliferation and chemoresistance; conversely, stabilizing PDCD5 (e.g., by OTUD5) or promoting its nuclear function enhances TP53-mediated apoptosis. In colorectal models, manipulating PDCD5 modulates sensitivity to oxaliplatin, and DHA augments PDCD5 nuclear localization and suppresses MAPK signaling. Together, these observations nominate PDCD5 and its regulators (JMJD4, OTUD5) as translational targets for chemosensitization strategies. URLs: https://doi.org/10.5483/bmbrep.2024-0027 (2024); https://doi.org/10.21203/rs.3.rs-3353635/v1 (2023); https://doi.org/10.3390/cells12081161 (2023). (kim2024jmjd4promotestumor pages 1-2, peng2023dihydroartemisininenhancesthe pages 14-16, kim2024jmjd4promotestumor pages 2-3, fu2023theregulationand pages 4-6, kim2024jmjd4promotestumor pages 3-5)

5) Expert opinions and mechanistic analysis from authoritative sources
- 2024 primary study (BMB Reports): Provides direct biochemical and cell-biological evidence that JMJD4 binds PDCD5 and lowers its protein stability to inhibit TP53-dependent apoptosis. The authors propose JMJD4 as a cancer-promoting factor via the PDCD5–TP53 axis and a potential therapeutic target, implying that PDCD5 protein stabilization could be beneficial in therapy. URL: https://doi.org/10.5483/bmbrep.2024-0027 (July 2024). (kim2024jmjd4promotestumor pages 1-2, kim2024jmjd4promotestumor pages 2-3, kim2024jmjd4promotestumor pages 3-5)
- 2023 mechanistic synthesis (OTUD5 review in Cells): Assembles evidence that OTUD5 deubiquitinates and stabilizes PDCD5 and TP53 under DNA damage, enabling rapid TP53 activation and apoptosis. This positions DUBs and the ubiquitin system as tuners of PDCD5-driven death signaling, suggesting druggability at the level of DUBs or E3 ligases controlling PDCD5. URL: https://doi.org/10.3390/cells12081161 (April 2023). (fu2023theregulationand pages 6-8, fu2023theregulationand pages 4-6)
- 2023 clinical RA study (Rheumatology and Therapy): Argues for PDCD5 as a practical blood biomarker with strong ROC characteristics and correlations to immunologic mediators, pointing to potential utility in monitoring disease activity and remission. URL: https://doi.org/10.1007/s40744-023-00587-5 (Aug 2023). (xiao2023pdcd5asa pages 1-2, xiao2023pdcd5asa pages 6-8)

6) Relevant statistics and data (selected 2023–2024)
- RA biomarker performance: AUC 0.846 (95% CI 0.780–0.912); sensitivity 86.6%; specificity 88.1%. Incidence risk per higher PDCD5: OR 1.73 (95% CI 1.45–1.98, P=0.005); high-risk group OR 2.94 (95% CI 2.35–4.62, P<0.001). URL: https://doi.org/10.1007/s40744-023-00587-5 (2023). (xiao2023pdcd5asa pages 6-8)
- Colon cancer cohort and model details: Tumor versus adjacent tissue analysis in 14 patients; PDCD5 overexpression/knockdown validated in HCT116 and RKO; in vivo xenograft data in BALB/c nude mice; DHA induced PDCD5 nuclear enrichment and enhanced oxaliplatin efficacy via PDCD5–ARAF pathway modulation. URL: https://doi.org/10.21203/rs.3.rs-3353635/v1 (2023). (peng2023dihydroartemisininenhancesthe pages 14-16)
- JMJD4–PDCD5 interaction mapping and impact: Direct binding mapped to JMJD4 aa 180–221 and PDCD5 aa 91–125; JMJD4 overexpression decreased PDCD5 protein without changing mRNA; proteasome dependence demonstrated; TP53 targets (BAX, PUMA) reduced upon JMJD4 overexpression under genotoxic stress. URL: https://doi.org/10.5483/bmbrep.2024-0027 (2024). (kim2024jmjd4promotestumor pages 2-3)

7) Clarifications on catalytic activity and molecular role
- PDCD5 is not an enzyme or transporter; it functions as a regulatory adaptor/scaffold whose abundance and localization tune pro-apoptotic transcriptional programs, especially in the TP53 pathway. Evidence supports direct and indirect actions: (i) protein–protein interactions that influence TP53 stability/output; (ii) coupling to ubiquitin signaling via DUBs (OTUD5) and degradation factors (JMJD4) that set PDCD5 protein steady-state; and (iii) subcellular relocalization to the nucleus during apoptotic signaling. URLs: 2024 BMB Reports https://doi.org/10.5483/bmbrep.2024-0027; 2023 Cells review https://doi.org/10.3390/cells12081161; 2023 Research Square preprint https://doi.org/10.21203/rs.3.rs-3353635/v1. (kim2024jmjd4promotestumor pages 1-2, kim2024jmjd4promotestumor pages 2-3, fu2023theregulationand pages 4-6, peng2023dihydroartemisininenhancesthe pages 14-16)

Limitations and open questions
- Structural and domain annotations (e.g., PDCD5-like domain, dsDNA_bind PF01984) and canonical Tip60/TP53 acetylation biochemistry were not retrievable within the 2023–2024 sources gathered here; however, the 2024 and 2023 studies provide convergent mechanistic evidence on PDCD5’s regulation of TP53-mediated apoptosis and on its nuclear relocalization under stress. Additional structural/domain confirmation would require consultation of curated databases or primary structural papers beyond the present evidence set. (kim2024jmjd4promotestumor pages 1-2, fu2023theregulationand pages 4-6)

Conclusions
PDCD5 (TFAR19) in humans is a nuclear-translocating, apoptosis-facilitating regulator that potentiates TP53-dependent death programs under genotoxic stress. Its activity is tuned by opposing ubiquitin-pathway regulators: OTUD5 stabilizes PDCD5 by deubiquitination, whereas JMJD4 promotes proteasomal degradation, collectively dictating TP53 output and chemosensitivity. Clinically, PDCD5 shows promise as a blood biomarker of rheumatoid arthritis activity and remission with strong performance metrics, and in oncology models PDCD5 status modulates response to chemotherapeutics and MAPK signaling via ARAF, suggesting actionable translational avenues. URLs: 2024 BMB Reports https://doi.org/10.5483/bmbrep.2024-0027; 2023 Cells review https://doi.org/10.3390/cells12081161; 2023 Rheumatology and Therapy https://doi.org/10.1007/s40744-023-00587-5; 2023 Research Square preprint https://doi.org/10.21203/rs.3.rs-3353635/v1. (kim2024jmjd4promotestumor pages 1-2, fu2023theregulationand pages 6-8, peng2023dihydroartemisininenhancesthe pages 14-16, kim2024jmjd4promotestumor pages 2-3, fu2023theregulationand pages 4-6, kim2024jmjd4promotestumor pages 3-5, xiao2023pdcd5asa pages 1-2, xiao2023pdcd5asa pages 6-8, xiao2023pdcd5asa pages 12-14, xiao2023pdcd5asa pages 14-15)

References

  1. (kim2024jmjd4promotestumor pages 1-2): Hyunsik Kim, Subhin Jang, Soo Yeon Lee, Jae-Hwan Kwon, Seunghee Byun, Jung-Yoon Yoo, Sungryul Yu, Soo-Yeon Park, and Ho-Geun Yoon. Jmjd4 promotes tumor progression via inhibition of the pdcd5-tp53 pathway. BMB Reports, 58:64-69, Jul 2024. URL: https://doi.org/10.5483/bmbrep.2024-0027, doi:10.5483/bmbrep.2024-0027. This article has 0 citations and is from a peer-reviewed journal.

  2. (kim2024jmjd4promotestumor pages 6-6): Hyunsik Kim, Subhin Jang, Soo Yeon Lee, Jae-Hwan Kwon, Seunghee Byun, Jung-Yoon Yoo, Sungryul Yu, Soo-Yeon Park, and Ho-Geun Yoon. Jmjd4 promotes tumor progression via inhibition of the pdcd5-tp53 pathway. BMB Reports, 58:64-69, Jul 2024. URL: https://doi.org/10.5483/bmbrep.2024-0027, doi:10.5483/bmbrep.2024-0027. This article has 0 citations and is from a peer-reviewed journal.

  3. (fu2023theregulationand pages 6-8): Lin Fu, Kun Lu, Qian Jiao, Xi Chen, and Fengju Jia. The regulation and double-edged roles of the deubiquitinase otud5. Cells, 12:1161, Apr 2023. URL: https://doi.org/10.3390/cells12081161, doi:10.3390/cells12081161. This article has 18 citations and is from a poor quality or predatory journal.

  4. (peng2023dihydroartemisininenhancesthe pages 14-16): Yanling Peng, Yingying Zheng, Juanjuan Qiu, Jing Liu, Jiaorui Zou, Chunyan Liu, and Zhengbin Chai. Dihydroartemisinin enhances the effects of oxaliplatin by activating pdcd5/araf mediated signal transduction in colon cancer. Sep 2023. URL: https://doi.org/10.21203/rs.3.rs-3353635/v1, doi:10.21203/rs.3.rs-3353635/v1.

  5. (kim2024jmjd4promotestumor pages 2-3): Hyunsik Kim, Subhin Jang, Soo Yeon Lee, Jae-Hwan Kwon, Seunghee Byun, Jung-Yoon Yoo, Sungryul Yu, Soo-Yeon Park, and Ho-Geun Yoon. Jmjd4 promotes tumor progression via inhibition of the pdcd5-tp53 pathway. BMB Reports, 58:64-69, Jul 2024. URL: https://doi.org/10.5483/bmbrep.2024-0027, doi:10.5483/bmbrep.2024-0027. This article has 0 citations and is from a peer-reviewed journal.

  6. (fu2023theregulationand pages 4-6): Lin Fu, Kun Lu, Qian Jiao, Xi Chen, and Fengju Jia. The regulation and double-edged roles of the deubiquitinase otud5. Cells, 12:1161, Apr 2023. URL: https://doi.org/10.3390/cells12081161, doi:10.3390/cells12081161. This article has 18 citations and is from a poor quality or predatory journal.

  7. (kim2024jmjd4promotestumor pages 3-5): Hyunsik Kim, Subhin Jang, Soo Yeon Lee, Jae-Hwan Kwon, Seunghee Byun, Jung-Yoon Yoo, Sungryul Yu, Soo-Yeon Park, and Ho-Geun Yoon. Jmjd4 promotes tumor progression via inhibition of the pdcd5-tp53 pathway. BMB Reports, 58:64-69, Jul 2024. URL: https://doi.org/10.5483/bmbrep.2024-0027, doi:10.5483/bmbrep.2024-0027. This article has 0 citations and is from a peer-reviewed journal.

  8. (xiao2023pdcd5asa pages 1-2): Juan Xiao, Fengqiao Zhou, Zhenwang Zhao, Fengsheng Cao, Hong Xiao, Lu Zhang, Huabo Chen, Ke Wang, and Anbing Zhang. Pdcd5 as a potential biomarker for improved prediction of the incidence and remission for patients with rheumatoid arthritis. Rheumatology and Therapy, 10:1369-1383, Aug 2023. URL: https://doi.org/10.1007/s40744-023-00587-5, doi:10.1007/s40744-023-00587-5. This article has 0 citations and is from a peer-reviewed journal.

  9. (xiao2023pdcd5asa pages 6-8): Juan Xiao, Fengqiao Zhou, Zhenwang Zhao, Fengsheng Cao, Hong Xiao, Lu Zhang, Huabo Chen, Ke Wang, and Anbing Zhang. Pdcd5 as a potential biomarker for improved prediction of the incidence and remission for patients with rheumatoid arthritis. Rheumatology and Therapy, 10:1369-1383, Aug 2023. URL: https://doi.org/10.1007/s40744-023-00587-5, doi:10.1007/s40744-023-00587-5. This article has 0 citations and is from a peer-reviewed journal.

  10. (xiao2023pdcd5asa pages 12-14): Juan Xiao, Fengqiao Zhou, Zhenwang Zhao, Fengsheng Cao, Hong Xiao, Lu Zhang, Huabo Chen, Ke Wang, and Anbing Zhang. Pdcd5 as a potential biomarker for improved prediction of the incidence and remission for patients with rheumatoid arthritis. Rheumatology and Therapy, 10:1369-1383, Aug 2023. URL: https://doi.org/10.1007/s40744-023-00587-5, doi:10.1007/s40744-023-00587-5. This article has 0 citations and is from a peer-reviewed journal.

  11. (xiao2023pdcd5asa pages 14-15): Juan Xiao, Fengqiao Zhou, Zhenwang Zhao, Fengsheng Cao, Hong Xiao, Lu Zhang, Huabo Chen, Ke Wang, and Anbing Zhang. Pdcd5 as a potential biomarker for improved prediction of the incidence and remission for patients with rheumatoid arthritis. Rheumatology and Therapy, 10:1369-1383, Aug 2023. URL: https://doi.org/10.1007/s40744-023-00587-5, doi:10.1007/s40744-023-00587-5. This article has 0 citations and is from a peer-reviewed journal.

Citations

  1. peng2023dihydroartemisininenhancesthe pages 14-16
  2. fu2023theregulationand pages 6-8
  3. fu2023theregulationand pages 4-6
  4. https://doi.org/10.5483/bmbrep.2024-0027
  5. https://doi.org/10.3390/cells12081161
  6. https://doi.org/10.21203/rs.3.rs-3353635/v1
  7. https://doi.org/10.5483/bmbrep.2024-0027;
  8. https://doi.org/10.3390/cells12081161.
  9. https://doi.org/10.1007/s40744-023-00587-5
  10. https://doi.org/10.3390/cells12081161;
  11. https://doi.org/10.21203/rs.3.rs-3353635/v1.
  12. https://doi.org/10.1007/s40744-023-00587-5;
  13. https://doi.org/10.5483/bmbrep.2024-0027,
  14. https://doi.org/10.3390/cells12081161,
  15. https://doi.org/10.21203/rs.3.rs-3353635/v1,
  16. https://doi.org/10.1007/s40744-023-00587-5,

πŸ“„ View Raw YAML

 
id: O14737
gene_symbol: PDCD5
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: >-
  PDCD5 (Programmed cell death protein 5, also known as TFAR19) is a pro-apoptotic regulatory
  adaptor protein that functions primarily as a positive regulator of the p53/TP53 tumor suppressor
  pathway. Under normal conditions, PDCD5 helps maintain basal levels of p53 and Tip60 (a histone
  acetyltransferase). Upon DNA damage or genotoxic stress, PDCD5 is phosphorylated at Ser-119 by
  CK2, which stabilizes the protein and promotes its translocation from cytosol to nucleus. In the
  nucleus, PDCD5 performs two key functions: (1) it binds to and activates Tip60, enhancing its HAT
  activity and Tip60-dependent K120 acetylation of p53; (2) it directly binds p53 and antagonizes
  MDM2-mediated p53 ubiquitination and degradation, thereby stabilizing p53 and promoting
  p53-dependent transcription of pro-apoptotic genes (BAX, PUMA). PDCD5 is also regulated by OTUD5
  (deubiquitinase that stabilizes it) and JMJD4/PPEF-1 (which promote its degradation). Beyond
  apoptosis, PDCD5 interacts with FOXP3 to enhance Treg function and suppress autoimmunity. It also
  inhibits beta-tubulin folding by binding to the CCT chaperonin complex, which may contribute to
  its anti-proliferative effects.
alternative_products:
- name: '1'
  id: O14737-1
- name: '2'
  id: O14737-2
  sequence_note: VSP_056203
existing_annotations:
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      PDCD5 nuclear localization is well-documented and represents a key functional location,
      particularly during genotoxic stress responses. Multiple primary studies demonstrate nuclear
      localization by immunofluorescence and fractionation [PMID:19308289, PMID:22914926,
      PMID:28051100, PMID:24012345]. The IBA annotation is consistent with phylogenetic conservation
      and experimental data.
    action: ACCEPT
    reason: >-
      Nuclear localization is essential for PDCD5 function in p53 activation and DNA damage
      response. CK2-mediated phosphorylation at Ser-119 promotes nuclear translocation during
      genotoxic stress [PMID:28051100].
    supported_by:
      - reference_id: PMID:28051100
        supporting_text: "PDCD5 phosphorylation at Ser-119 is rapidly induced by the genotoxic stress response, which stabilizes the protein and results in PDCD5 nuclear translocation"
      - reference_id: PMID:19308289
        supporting_text: "PDCD5 levels increase significantly on DNA damage in U2OS cells"

- term:
    id: GO:0005829
    label: cytosol
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      PDCD5 is found in the cytosol under basal conditions and translocates to the nucleus upon
      DNA damage or genotoxic stress. The cytosolic localization represents its resting state
      location [PMID:28051100]. This dual localization is consistent with its function as a
      stress-responsive signaling molecule.
    action: ACCEPT
    reason: >-
      Cytosolic localization is the default location for PDCD5 in unstressed cells. Upon
      phosphorylation at Ser-119, PDCD5 translocates to the nucleus for its pro-apoptotic function.
    supported_by:
      - reference_id: PMID:28051100
        supporting_text: "PDCD5 phosphorylation is maintained at a low level in the absence of genotoxic stress"

- term:
    id: GO:0003677
    label: DNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      This annotation is derived from InterPro domain mapping (PDCD5-like domain, dsDNA_bind PF01984).
      While the structural similarity suggests potential DNA binding capability, there is limited
      direct experimental evidence for PDCD5 DNA binding activity in primary literature. The deep
      research report notes that "Structural and domain annotations... were not retrievable within
      the 2023-2024 sources."
    action: UNDECIDED
    reason: >-
      The annotation is based on domain homology but lacks direct experimental validation. PDCD5
      functions primarily through protein-protein interactions (with Tip60, p53, MDM2, FOXP3, CCT)
      rather than direct DNA binding. The ChIP experiment in PMID:22914926 shows PDCD5 association
      at the p21 promoter, but this may be indirect through p53 binding rather than direct DNA binding.
    additional_reference_ids:
      - PMID:22914926

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:19308289
  review:
    summary: >-
      This annotation indicates PDCD5 binds to Tip60 (Q92993). PMID:19308289 demonstrates that
      "PDCD5 binds to Tip60 and enhances the stability of Tip60 protein" and "The binding amount
      of PDCD5 and Tip60 is significantly increased after UV irradiation."
    action: MODIFY
    reason: >-
      While the interaction with Tip60 is valid and experimentally demonstrated, the generic
      'protein binding' term is uninformative. PDCD5 functions as a Tip60 coactivator, enhancing
      its acetyltransferase activity. A more specific term should be used.
    proposed_replacement_terms:
      - id: GO:0010698
        label: acetyltransferase activator activity
    supported_by:
      - reference_id: PMID:19308289
        supporting_text: "PDCD5 enhances HAT activity of Tip60 and Tip60-dependent histone acetylation in both basal and UV-induced levels"

- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:19308289
  review:
    summary: >-
      Direct experimental evidence from PMID:19308289 showing nuclear localization. The study
      demonstrates co-localization with Tip60 in the nucleus and increased nuclear PDCD5 after
      DNA damage.
    action: ACCEPT
    reason: >-
      Primary experimental data demonstrating nuclear localization. This is consistent with
      PDCD5's function in the p53 pathway and DNA damage response.
    supported_by:
      - reference_id: PMID:19308289
        supporting_text: "PDCD5 levels increase significantly on DNA damage in U2OS cells, as does Tip60"

- term:
    id: GO:0006915
    label: apoptotic process
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: >-
      This annotation is derived from the UniProt keyword "Apoptosis" (KW-0053). PDCD5 is indeed
      involved in apoptosis, as extensively documented in primary literature. It was originally
      cloned as an apoptosis-related gene [PMID:9920759] and promotes apoptosis through the
      p53/Tip60 pathway [PMID:19308289, PMID:22914926].
    action: MODIFY
    reason: >-
      The annotation is correct but too general. PDCD5 specifically promotes apoptosis rather
      than just being "involved in" it. The more specific term GO:0043065 (positive regulation
      of apoptotic process) or GO:1902255 (positive regulation of intrinsic apoptotic signaling
      pathway by p53 class mediator) better captures its function.
    proposed_replacement_terms:
      - id: GO:0043065
        label: positive regulation of apoptotic process

- term:
    id: GO:0140311
    label: protein sequestering activity
  evidence_type: IDA
  original_reference_id: PMID:19308289
  review:
    summary: >-
      This annotation relates to PDCD5's function in sequestering proteins. According to
      PMID:19308289, PDCD5 binds Tip60 and stabilizes it. From PMID:22914926, PDCD5 binds p53
      and antagonizes MDM2-mediated p53 degradation by "dissociating the interaction between
      p53 and Mdm2."
    action: ACCEPT
    reason: >-
      PDCD5 does function to sequester/stabilize binding partners (Tip60, p53) away from
      degradation pathways. It prevents MDM2 from binding p53 by directly interacting with
      both proteins.
    supported_by:
      - reference_id: PMID:22914926
        supporting_text: "PDCD5 could dissociate the interaction between p53 and Mdm2 and interact with Mdm2 directly to promote its degradation"

- term:
    id: GO:1901798
    label: positive regulation of signal transduction by p53 class mediator
  evidence_type: IMP
  original_reference_id: PMID:19308289
  review:
    summary: >-
      PMID:19308289 demonstrates that PDCD5 enhances p53 signaling through Tip60-mediated K120
      acetylation of p53 and participates in p53-dependent expression of pro-apoptotic genes
      like Bax. Knockdown of PDCD5 impairs p53-dependent apoptosis.
    action: ACCEPT
    reason: >-
      This represents a core function of PDCD5. The protein positively regulates p53 signaling
      at multiple levels: stabilizing p53 protein, enhancing p53 acetylation via Tip60, and
      promoting p53-dependent gene transcription.
    supported_by:
      - reference_id: PMID:19308289
        supporting_text: "PDCD5 increases Tip60-dependent K120 acetylation of p53 and participates in the p53-dependent expression of apoptosis-related genes, such as Bax"

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:32296183
  review:
    summary: >-
      This annotation is from high-throughput binary protein interactome mapping (HuRI).
      The interacting partners listed include PICK1 (Q9NRD5), RAD18 (Q9NS91), and TRIM35
      (Q9UPQ4-2). These are from a systematic screen rather than hypothesis-driven studies.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      High-throughput interactome studies often identify many interactions. While these
      interactions may be real, the generic 'protein binding' term provides no functional
      insight. The biological significance of PDCD5 interactions with PICK1, RAD18, or
      TRIM35 has not been characterized in follow-up studies.

- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:22914926
  review:
    summary: >-
      PMID:22914926 confirms nuclear localization through co-localization assays and shows
      PDCD5 associates with p53 at the p21 promoter by ChIP. This study provides independent
      confirmation of nuclear localization.
    action: ACCEPT
    reason: >-
      Multiple lines of evidence confirm nuclear localization. This study adds ChIP data
      showing PDCD5 at chromatin in the nucleus.
    supported_by:
      - reference_id: PMID:22914926
        supporting_text: "chromatin immunoprecipitation assays showed an up-regulated association of PDCD5 at the p53BS2 site of the p21 promoter during DNA damage"

- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:28051100
  review:
    summary: >-
      PMID:28051100 demonstrates nuclear localization by immunofluorescence and shows that
      phosphorylation at Ser-119 promotes nuclear translocation. PPEF-1 dephosphorylates
      PDCD5 and prevents nuclear accumulation.
    action: ACCEPT
    reason: >-
      This study provides mechanistic insight into how PDCD5 nuclear localization is
      regulated by phosphorylation status.
    supported_by:
      - reference_id: PMID:28051100
        supporting_text: "ET treatment rapidly induced nuclear accumulation of PDCD5... Wild-type PPEF-1 completely abrogated PDCD5 stabilization in response to ET"

- term:
    id: GO:0042110
    label: T cell activation
  evidence_type: IPI
  original_reference_id: PMID:24012345
  review:
    summary: >-
      PMID:24012345 shows PDCD5 interacts with FOXP3 (Q9BZS1) in T cells. The study
      demonstrates that PDCD5 enhances FOXP3 function, increases Treg cell frequency, and
      suppresses Th17/Th1 responses. However, the annotation suggests PDCD5 promotes T cell
      activation, which is the opposite of what the paper shows.
    action: MODIFY
    reason: >-
      The annotation is misleading. PDCD5 does not promote T cell activation but rather
      suppresses it by enhancing regulatory T cell (Treg) function and inhibiting effector
      T cell responses. A term related to Treg regulation would be more appropriate.
    proposed_replacement_terms:
      - id: GO:0045066
        label: regulatory T cell differentiation
    supported_by:
      - reference_id: PMID:24012345
        supporting_text: "PDCD5 negatively regulates autoimmunity by upregulating FOXP3(+) regulatory T cells and suppressing Th17 and Th1 responses"

- term:
    id: GO:0140311
    label: protein sequestering activity
  evidence_type: IDA
  original_reference_id: PMID:22914926
  review:
    summary: >-
      PMID:22914926 demonstrates that PDCD5 binds p53 and sequesters it from MDM2-mediated
      degradation. PDCD5 also directly interacts with MDM2 to promote its degradation.
    action: ACCEPT
    reason: >-
      Protein sequestering activity accurately describes PDCD5's mechanism of protecting
      p53 from MDM2.
    supported_by:
      - reference_id: PMID:22914926
        supporting_text: "PDCD5 enhanced the stability of p53 by antagonizing Mdm2-induced p53 ubiquitination, nuclear export and proteasomal degradation"

- term:
    id: GO:1901798
    label: positive regulation of signal transduction by p53 class mediator
  evidence_type: IMP
  original_reference_id: PMID:22914926
  review:
    summary: >-
      PMID:22914926 provides extensive IMP evidence for PDCD5 positive regulation of p53
      signaling. Knockdown of PDCD5 decreases p53 phosphorylation and p21 expression, while
      PDCD5 is required for G1 arrest during DNA damage.
    action: ACCEPT
    reason: >-
      Core function of PDCD5. This study provides complementary evidence to PMID:19308289.
    supported_by:
      - reference_id: PMID:22914926
        supporting_text: "knockdown of PDCD5 by RNA interference decreased the p53 phosphorylation at Ser9, 20 and 392 residues, as well as the expression of p21 protein"

- term:
    id: GO:1902255
    label: positive regulation of intrinsic apoptotic signaling pathway by p53 class mediator
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: >-
      This ISS annotation is transferred from mouse PDCD5 (UniProtKB:P56812) based on
      sequence similarity. The term is highly specific and consistent with PDCD5's function
      in promoting p53-mediated apoptosis through the intrinsic (mitochondrial) pathway.
    action: ACCEPT
    reason: >-
      The annotation is consistent with PDCD5's established function. PMID:16374546 shows
      PDCD5 is involved in cytochrome c release and Bax translocation to mitochondria,
      which are hallmarks of the intrinsic apoptotic pathway.
    supported_by:
      - reference_id: PMID:16374546
        supporting_text: "Suppressed expression of PDCD5 attenuates the release of cytochrome c from mitochondria to cytosol induced by Bax overexpression"

- term:
    id: GO:0042981
    label: regulation of apoptotic process
  evidence_type: IMP
  original_reference_id: PMID:16374546
  review:
    summary: >-
      PMID:16374546 demonstrates that siRNA knockdown of PDCD5 attenuates apoptosis and
      caspase-3 activity induced by Bax overexpression. The paper shows PDCD5 modulates
      Bax translocation and cytochrome c release.
    action: MODIFY
    reason: >-
      While accurate, this term is less specific than the evidence supports. PDCD5
      specifically promotes apoptosis (positive regulation), not merely regulates it
      in an unspecified direction.
    proposed_replacement_terms:
      - id: GO:0043065
        label: positive regulation of apoptotic process
    supported_by:
      - reference_id: PMID:16374546
        supporting_text: "The programmed cell death 5 (PDCD5) protein plays an important apoptosis-accelerating role in cells undergoing apoptosis"

- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: HDA
  original_reference_id: PMID:16791210
  review:
    summary: >-
      This high-throughput localization study (PMID:16791210) used YFP-tagged proteins to
      systematically study nuclear protein dynamics. The detection of PDCD5 in cytoplasm is
      consistent with its known cytosol-to-nucleus translocation pattern.
    action: ACCEPT
    reason: >-
      While HDA evidence is lower quality than IDA, the cytoplasmic localization is
      consistent with extensive literature showing PDCD5 in cytosol under basal conditions.
    supported_by:
      - reference_id: PMID:28051100
        supporting_text: "PDCD5 protein is maintained at a low level in the absence of genotoxic stress response"

- term:
    id: GO:0010698
    label: acetyltransferase activator activity
  evidence_type: IDA
  original_reference_id: PMID:24012345
  review:
    summary: >-
      PMID:24012345 shows PDCD5 "increases acetylation of FOXP3 in synergy with Tip60."
      This is consistent with earlier work (PMID:19308289) showing PDCD5 enhances Tip60
      HAT activity. PDCD5 acts as a coactivator for Tip60-mediated acetylation.
    action: ACCEPT
    reason: >-
      Core molecular function of PDCD5. It enhances the acetyltransferase activity of
      Tip60 on multiple substrates including p53 and FOXP3.
    supported_by:
      - reference_id: PMID:24012345
        supporting_text: "PDCD5 interacts with FOXP3, increases acetylation of FOXP3 in synergy with Tip60"
      - reference_id: PMID:19308289
        supporting_text: "PDCD5 enhances HAT activity of Tip60"

- term:
    id: GO:0071560
    label: cellular response to transforming growth factor beta stimulus
  evidence_type: IDA
  original_reference_id: PMID:24012345
  review:
    summary: >-
      PMID:24012345 demonstrates that naive CD4+ T cells from PDCD5 transgenic mice are
      "more sensitive to TGF-beta-induced Treg polarization and expansion." This indicates
      PDCD5 modulates the cellular response to TGF-beta.
    action: KEEP_AS_NON_CORE
    reason: >-
      This is a genuine function but represents a context-specific role in T cells
      rather than the core molecular function of PDCD5 (which is p53/Tip60 pathway
      regulation). The TGF-beta response relates to PDCD5's role in Treg differentiation.
    supported_by:
      - reference_id: PMID:24012345
        supporting_text: "NaΓ―ve CD4(+) T cells from PDCD5tg mice were more sensitive to TGF-Ξ²-induced Treg polarization and expansion"

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:24012345
  review:
    summary: >-
      This annotation indicates PDCD5 binds FOXP3 (Q9BZS1). PMID:24012345 demonstrates
      that "PDCD5 interacts with FOXP3" through biochemical assays.
    action: MODIFY
    reason: >-
      The generic 'protein binding' term is uninformative. PDCD5 functions as a FOXP3
      coactivator, enhancing FOXP3 acetylation and stability. A more specific functional
      term should be used.
    proposed_replacement_terms:
      - id: GO:0010698
        label: acetyltransferase activator activity
    supported_by:
      - reference_id: PMID:24012345
        supporting_text: "PDCD5 interacts with FOXP3, increases acetylation of FOXP3 in synergy with Tip60 and enhances the repressive function of FOXP3"

- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:24012345
  review:
    summary: >-
      Another independent IDA confirmation of nuclear localization from PMID:24012345.
    action: ACCEPT
    reason: >-
      Multiple IDA annotations for nuclear localization from different labs confirm
      this is a well-established location for PDCD5 function.

- term:
    id: GO:0048487
    label: beta-tubulin binding
  evidence_type: IPI
  original_reference_id: PMID:24375412
  review:
    summary: >-
      PMID:24375412 demonstrates that "PDCD5 formed a complex with CCT and beta-tubulin"
      and specifically inhibits beta-tubulin folding. The interaction was mapped by
      cryo-EM to the CCTbeta apical domain.
    action: ACCEPT
    reason: >-
      The beta-tubulin binding is experimentally validated and functionally significant.
      It provides a mechanism for PDCD5's anti-proliferative effects through inhibition
      of tubulin folding.
    supported_by:
      - reference_id: PMID:24375412
        supporting_text: "PDCD5 formed a complex with CCT and beta-tubulin, a key CCT-folding substrate, and specifically inhibited beta-tubulin folding"

- term:
    id: GO:1903333
    label: negative regulation of protein folding
  evidence_type: IMP
  original_reference_id: PMID:24375412
  review:
    summary: >-
      PMID:24375412 shows PDCD5 inhibits beta-tubulin folding by binding to the CCT
      chaperonin and sterically interfering with substrate access.
    action: KEEP_AS_NON_CORE
    reason: >-
      This is a validated function but represents a distinct mechanism from PDCD5's
      primary role in p53/Tip60 pathway regulation. It may contribute to PDCD5's
      anti-proliferative effects but is not its core function in apoptosis.
    supported_by:
      - reference_id: PMID:24375412
        supporting_text: "PDCD5 might exert its apoptotic function at least in part through inhibition of beta-tubulin folding"

- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:24375412
  review:
    summary: >-
      This annotation indicates PDCD5 binds CCT5/TCP-1 epsilon (P48643). The interaction
      was characterized by proteomics and cryo-EM.
    action: MODIFY
    reason: >-
      Generic 'protein binding' is uninformative. The interaction with CCT has a
      specific functional consequence (inhibition of beta-tubulin folding).
    proposed_replacement_terms:
      - id: GO:0051087
        label: chaperone binding
    supported_by:
      - reference_id: PMID:24375412
        supporting_text: "A proteomics search for binding partners of phosducin-like protein, a co-chaperone for the cytosolic chaperonin containing tailless complex polypeptide 1 (CCT), revealed a robust interaction between PDCD5 and CCT"

- term:
    id: GO:0008201
    label: heparin binding
  evidence_type: IDA
  original_reference_id: PMID:17165023
  review:
    summary: >-
      PMID:17165023 uses capillary zone electrophoresis to demonstrate PDCD5-heparin
      interaction with a binding constant of 4.17 x 10^4 M^-1. However, the biological
      significance of this interaction is unclear.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      While the biochemical interaction is documented, the physiological relevance of
      PDCD5 binding to heparin is not established. This appears to be an in vitro
      finding without clear in vivo significance. The paper is primarily a methods
      paper for CZE analysis.
    supported_by:
      - reference_id: PMID:17165023
        supporting_text: "The binding constant of the interaction between PDCD5 and heparin was calculated as 4.17 x 10(4) M(-1) by Scatchard analysis"

- term:
    id: GO:0070062
    label: extracellular exosome
  evidence_type: HDA
  original_reference_id: PMID:20458337
  review:
    summary: >-
      High-throughput detection of PDCD5 in B-cell exosomes. The biological significance
      of exosomal PDCD5 is not characterized.
    action: KEEP_AS_NON_CORE
    reason: >-
      While the localization in exosomes may be real (HDA evidence from proteomics),
      this does not represent a functional location for PDCD5's characterized activities.
      It may represent secretion/clearance rather than active function.

- term:
    id: GO:0043065
    label: positive regulation of apoptotic process
  evidence_type: IMP
  original_reference_id: PMID:9920759
  review:
    summary: >-
      This is the original paper identifying PDCD5 (TFAR19). It shows overexpression of
      PDCD5 "enhances apoptosis triggered by growth factor or serum deprivation" in tumor
      cells. This established PDCD5 as a pro-apoptotic factor.
    action: ACCEPT
    reason: >-
      This is the foundational paper for PDCD5 function. Positive regulation of apoptosis
      is the core function of PDCD5, extensively validated by subsequent studies.
    supported_by:
      - reference_id: PMID:9920759
        supporting_text: "Overexpression of TFAR19 in tumor cells enhances apoptosis triggered by growth factor or serum deprivation"

references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO terms
  findings: []
- id: GO_REF:0000024
  title: Manual transfer of experimentally-verified manual GO annotation data to orthologs
    by curator judgment of sequence similarity
  findings: []
- 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: PMID:9920759
  title: TFAR19, a novel apoptosis-related gene cloned from human leukemia cell line
    TF-1, could enhance apoptosis of some tumor cells induced by growth factor withdrawal.
  findings:
    - statement: Original identification of PDCD5/TFAR19 as pro-apoptotic factor
- id: PMID:16374546
  title: Short interfering RNA against the PDCD5 attenuates cell apoptosis and caspase-3
    activity induced by Bax overexpression.
  findings:
    - statement: PDCD5 knockdown reduces apoptosis
    - statement: PDCD5 modulates Bax translocation and cytochrome c release
- id: PMID:16791210
  title: Dynamic proteomics in individual human cells uncovers widespread cell-cycle
    dependence of nuclear proteins.
  findings:
    - statement: High-throughput proteomics detecting PDCD5 localization
- id: PMID:17165023
  title: Studies on interactions of programmed cell death 5 (PDCD5) and its related
    peptides with heparin by capillary zone electrophoresis.
  findings:
    - statement: In vitro heparin binding demonstrated
- id: PMID:19308289
  title: PDCD5 interacts with Tip60 and functions as a cooperator in acetyltransferase
    activity and DNA damage-induced apoptosis.
  findings:
    - statement: PDCD5 binds and stabilizes Tip60
    - statement: PDCD5 enhances Tip60 HAT activity
    - statement: PDCD5 promotes p53 K120 acetylation via Tip60
    - statement: Nuclear localization after DNA damage
- id: PMID:20458337
  title: MHC class II-associated proteins in B-cell exosomes and potential functional
    implications for exosome biogenesis.
  findings:
    - statement: PDCD5 detected in B-cell exosomes
- id: PMID:22914926
  title: PDCD5 interacts with p53 and functions as a positive regulator in the p53 pathway.
  findings:
    - statement: PDCD5 directly binds p53
    - statement: PDCD5 antagonizes MDM2-mediated p53 degradation
    - statement: PDCD5 promotes p53 phosphorylation
    - statement: ChIP shows PDCD5 at p21 promoter
- id: PMID:24012345
  title: PDCD5 negatively regulates autoimmunity by upregulating FOXP3(+) regulatory
    T cells and suppressing Th17 and Th1 responses.
  findings:
    - statement: PDCD5 interacts with FOXP3
    - statement: PDCD5 enhances FOXP3 acetylation with Tip60
    - statement: PDCD5 promotes Treg differentiation
    - statement: TGF-beta sensitivity enhanced in PDCD5 transgenic mice
- id: PMID:24375412
  title: Programmed cell death protein 5 interacts with the cytosolic chaperonin containing
    tailless complex polypeptide 1 (CCT) to regulate Ξ²-tubulin folding.
  findings:
    - statement: PDCD5 binds CCT chaperonin
    - statement: PDCD5 inhibits beta-tubulin folding
    - statement: Cryo-EM structure of PDCD5-CCT complex
- id: PMID:28051100
  title: Protein serine/threonine phosphatase PPEF-1 suppresses genotoxic stress response
    via dephosphorylation of PDCD5.
  findings:
    - statement: PPEF-1 dephosphorylates PDCD5 at Ser-119
    - statement: Phosphorylation promotes nuclear localization
    - statement: CK2 phosphorylates, PPEF-1 dephosphorylates
- id: PMID:32296183
  title: A reference map of the human binary protein interactome.
  findings:
    - statement: High-throughput interactome data

core_functions:
- description: >-
    PDCD5 promotes apoptosis through multiple mechanisms: enhancing Tip60 HAT activity,
    stabilizing p53 by antagonizing MDM2, and promoting cytochrome c release. This is
    the primary function for which PDCD5 was discovered and named.
  molecular_function:
    id: GO:0010698
    label: acetyltransferase activator activity
  directly_involved_in:
    - id: GO:0043065
      label: positive regulation of apoptotic process
    - id: GO:1901798
      label: positive regulation of signal transduction by p53 class mediator
  locations:
    - id: GO:0005634
      label: nucleus
    - id: GO:0005829
      label: cytosol

- description: >-
    PDCD5 sequesters p53 from MDM2-mediated degradation by directly binding both proteins
    and disrupting the MDM2-p53 interaction, thereby stabilizing p53 protein levels.
  molecular_function:
    id: GO:0140311
    label: protein sequestering activity
  directly_involved_in:
    - id: GO:1901798
      label: positive regulation of signal transduction by p53 class mediator
  locations:
    - id: GO:0005634
      label: nucleus

suggested_questions:
- question: What is the structural basis for PDCD5's dual functions in Tip60 activation and CCT inhibition?
- question: Is the heparin binding activity physiologically relevant?
- question: What determines whether PDCD5 promotes p53 stabilization vs. its role in Treg function?

suggested_experiments:
- description: >-
    ChIP-seq for PDCD5 to determine genome-wide chromatin binding. This would clarify
    whether PDCD5 has DNA binding activity or only associates with chromatin indirectly
    through p53.
  hypothesis: >-
    PDCD5 associates with chromatin indirectly through p53 rather than via direct DNA binding.
- description: >-
    Structural studies of PDCD5-Tip60 complex to reveal the molecular mechanism of
    Tip60 activation by PDCD5.
  hypothesis: >-
    PDCD5 binding to Tip60 induces conformational changes that enhance HAT activity.