Cellulose synthase-like protein D3 (CSLD3) from Arachis hypogaea, a member of the glycosyltransferase family 2 (GT2) within the plant cellulose synthase-like D (CSLD) subfamily. The protein contains a cellulose synthase domain (PF03552), an N-terminal zinc finger RING domain, and multiple transmembrane helices consistent with integral membrane glycosyltransferase topology. CSLD proteins use GDP-mannose or UDP-glucose as donor substrates to synthesize beta-1,4-linked mannan or glucomannan polysaccharides that are components of hemicellulose in plant cell walls. In Arabidopsis, CSLD3 orthologs function at sites of rapid polarized cell wall deposition such as root hair tips, pollen tubes, and during cell plate formation. The protein is synthesized in the ER, assembled in the Golgi apparatus, and trafficked to the plasma membrane where it catalyzes polysaccharide biosynthesis. No direct experimental characterization exists for this specific peanut protein; functional annotation is inferred from conserved domain architecture and extensive characterization of CSLD orthologs in model plants.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0000139
Golgi membrane
|
IEA
GO_REF:0000044 |
ACCEPT |
Summary: Golgi membrane localization is consistent with the biosynthetic trafficking route of CSLD proteins. CESA/CSLD proteins are synthesized in the ER, assembled into complexes in the Golgi, and trafficked to the plasma membrane. The Golgi is a transit compartment rather than the primary site of function.
Reason: UniProt subcellular location annotation places this protein at the Golgi apparatus membrane as a multi-pass membrane protein, consistent with CSLD protein biology. The Golgi is where CSL protein complexes are assembled before delivery to the plasma membrane.
Supporting Evidence:
file:ARAHY/A0A444Z7V7/A0A444Z7V7-uniprot.txt
SUBCELLULAR LOCATION: Golgi apparatus membrane
file:ARAHY/A0A444Z7V7/A0A444Z7V7-deep-research-falcon.md
Individual CESA proteins are transported to the Golgi, where they assemble into cellulose synthase complexes
|
|
GO:0005737
cytoplasm
|
IEA
GO_REF:0000117 |
MARK AS OVER ANNOTATED |
Summary: Cytoplasm is an overly broad localization for this integral membrane protein. The protein traverses membranes with multiple transmembrane helices and its catalytic domain faces the cytoplasmic side, but calling it a cytoplasmic protein is misleading. More specific terms (Golgi membrane, plasma membrane, endomembrane system) are already annotated.
Reason: ARBA-derived annotation. While the catalytic domain is cytoplasm-facing, the protein is an integral membrane glycosyltransferase with 7 predicted transmembrane helices. Calling it cytoplasmic is uninformative given that more specific membrane localizations are already annotated.
|
|
GO:0009409
response to cold
|
IEA
GO_REF:0000117 |
MARK AS OVER ANNOTATED |
Summary: Response to cold is a pleiotropic stress annotation with no clear mechanistic connection to cellulose synthase-like protein function. While cell wall remodeling genes can be transcriptionally responsive to cold stress in plants, this does not establish that cold response is a core or even direct function of this protein. ARBA rules often propagate broad stress-response annotations based on expression patterns in distantly related species.
Reason: ARBA-derived annotation. Cold-responsive transcriptional changes in cell wall genes are a secondary consequence of stress-induced growth adjustments, not a direct molecular function of this glycosyltransferase. No specific evidence links CSLD3-type proteins to cold stress response pathways.
|
|
GO:0012505
endomembrane system
|
IEA
GO_REF:0000117 |
KEEP AS NON CORE |
Summary: Endomembrane system is a correct but very broad localization. The protein transits through the ER and Golgi (parts of the endomembrane system) during biosynthesis and trafficking to the plasma membrane. This annotation is subsumed by the more specific Golgi membrane annotation.
Reason: ARBA-derived annotation. Technically correct since the Golgi is part of the endomembrane system, but redundant with the more specific GO:0000139 (Golgi membrane) annotation.
|
|
GO:0016020
membrane
|
IEA
GO_REF:0000002 |
KEEP AS NON CORE |
Summary: Membrane is a very broad localization. The protein is clearly an integral membrane protein with multiple transmembrane helices, but this generic annotation is subsumed by more specific membrane annotations (Golgi membrane).
Reason: InterPro-derived annotation from the cellulose synthase domain (IPR005150). Correct but uninformative given more specific membrane annotations already present.
|
|
GO:0016760
cellulose synthase (UDP-forming) activity
|
IEA
GO_REF:0000002 |
MODIFY |
Summary: This annotation derives from the InterPro cellulose synthase domain (IPR005150), which covers the entire CESA/CSL superfamily. However, this protein belongs to the CSLD (cellulose synthase-like D) subfamily, not the true CESA subfamily. CSLD proteins have been shown to have mannan synthase and glucomannan synthase activities rather than (or in addition to) cellulose synthase activity. The InterPro2GO mapping is overly specific for CSLD subfamily members. A more appropriate annotation would be beta-1,4-mannan synthase activity or a more general transferase activity term.
Reason: The protein is classified in the plant cellulose synthase-like D subfamily per UniProt. CSLD proteins synthesize mannans and glucomannans rather than cellulose. The cellulose synthase (UDP-forming) activity term is a mis-annotation arising from the broad IPR005150 domain covering the entire CESA/CSL superfamily.
Proposed replacements:
mannan synthase activity
|
|
GO:0030244
cellulose biosynthetic process
|
IEA
GO_REF:0000002 |
MODIFY |
Summary: Like the cellulose synthase activity annotation, this process annotation derives from the broad IPR005150 domain mapping. CSLD subfamily proteins are involved in mannan and glucomannan biosynthesis rather than cellulose biosynthesis per se. While CSLD proteins contribute to cell wall biosynthesis, the specific process is hemicellulose (mannan) synthesis, not cellulose synthesis.
Reason: CSLD proteins synthesize mannans/glucomannans, which are hemicellulose components, not cellulose. A more appropriate process term would be mannan biosynthetic process or cell wall organization.
Proposed replacements:
cell wall organization
|
|
GO:0051753
mannan synthase activity
|
IEA
GO_REF:0000117 |
ACCEPT |
Summary: Mannan synthase activity is the most appropriate molecular function annotation for a CSLD subfamily protein. CSLD proteins use GDP-mannose as a donor substrate to synthesize beta-1,4-mannan polysaccharides, which are hemicellulose components of the plant cell wall. This ARBA-derived annotation correctly captures the enzymatic activity of CSLD proteins.
Reason: CSLD subfamily proteins have been experimentally shown to possess mannan synthase activity in multiple plant species. This is consistent with the protein being classified in the plant cellulose synthase-like D subfamily.
|
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.
The gene A0A444Z7V7 from Arachis hypogaea (peanut) encodes a cellulose synthase domain-containing protein belonging to the glycosyltransferase family 2 (GT2). While no direct experimental studies exist for this specific peanut protein, functional annotation can be confidently inferred from the protein's conserved domain architecture and extensive characterization of homologous cellulose synthase (CESA) proteins across plant species. This report synthesizes current understanding from recent authoritative literature (prioritizing 2023-2024 sources) to describe the molecular function, subcellular localization, and pathway involvement of this protein.
Plant cellulose synthase proteins belong to the GT2 family of glycosyltransferases, which represents the largest family in the CAZy database (jayachandran2024cellfreeexpressionand pages 1-5). Members of this family are membrane-integrated processive glycosyltransferases that synthesize ฮฒ-1,4-linked polysaccharides (verma2023insightsintosubstrate pages 1-5, huang2023pointmutationsin pages 1-2). The GT2 family includes cellulose synthases, hyaluronan synthases, chitin synthases, and other polysaccharide-synthesizing enzymes (jayachandran2024cellfreeexpressionand pages 1-5).
CESA proteins are highly conserved across plant species and contain characteristic structural features including: (1) zinc finger domains at the N-terminus, (2) eight transmembrane domains, (3) a large cytosolic catalytic domain containing conserved motifs (DDG, DXD, TED, and QXXRW), and (4) a plant-conserved region (PCR) and class-specific region (CSR) (huang2023pointmutationsin pages 1-2, zhang2025cellulosesynthasetacesa7 pages 1-2).
Cellulose synthase catalyzes the transfer of glucose from UDP-glucose (the donor substrate) to the C4 hydroxyl group at the non-reducing end of the nascent cellulose polymer (the acceptor substrate), forming ฮฒ-1,4-glycosidic linkages (verma2023insightsintosubstrate pages 1-5). This processive glycosyltransferase activity synthesizes long chains of ฮฒ-1,4-glucan polymers that constitute cellulose microfibrils (jayachandran2024cellfreeexpressionand pages 1-5, verma2023insightsintosubstrate pages 1-5).
The catalytic mechanism involves:
1. Substrate binding: UDP-glucose binds to a conserved catalytic pocket adjacent to the entrance of a transmembrane channel (verma2023insightsintosubstrate pages 1-5)
2. Glycosyl transfer: The glucosyl unit is transferred via an inverting mechanism typical of GT2 family enzymes (jayachandran2024cellfreeexpressionand pages 1-5)
3. Polymer translocation: Cellulose synthase uniquely couples polymer elongation with translocation of the growing cellulose chain across the plasma membrane through its own transmembrane pore (jayachandran2024cellfreeexpressionand pages 1-5, verma2023insightsintosubstrate pages 1-5)
The catalytic domain contains several conserved motifs essential for enzymatic function (huang2023pointmutationsin pages 1-2):
- DDG motif: Involved in substrate coordination and complex assembly
- DXD motif: Required for UDP-glucose binding and catalytic activity
- TED motif: Participates in acceptor substrate positioning
- QXXRW motif: Critical for protein folding, complex formation, and catalysis
Site-directed mutagenesis studies in Arabidopsis CESA6 demonstrate that mutations in these conserved motifs not only impair catalytic activity but also disrupt protein trafficking and cellulose synthase complex (CSC) formation, underscoring their multifunctional importance (huang2023pointmutationsin pages 1-2).
Cellulose synthase performs its catalytic function at the plasma membrane, where it actively synthesizes cellulose at the cell surface (huang2023pointmutationsin pages 1-2, zhang2025cellulosesynthasetacesa7 pages 1-2, cosgrove2024structureandgrowth pages 1-4, gu2022cellbiologyof pages 1-2). This plasma membrane localization has been confirmed across multiple plant species including wheat (TaCESA7 was shown to localize on the plasma membrane in dimeric form) (zhang2025cellulosesynthasetacesa7 pages 1-2) and Arabidopsis (huang2023pointmutationsin pages 1-2, liu2023actomyosinandcsi1pom2 pages 1-2).
The journey of cellulose synthase from synthesis to its functional location involves multiple cellular compartments (liu2023actomyosinandcsi1pom2 pages 1-2, gu2022cellbiologyof pages 1-2):
Endoplasmic Reticulum (ER): CESA proteins are synthesized at the ER and begin folding (huang2023pointmutationsin pages 1-2, liu2023actomyosinandcsi1pom2 pages 1-2)
Golgi Apparatus: Individual CESA proteins are transported to the Golgi, where they assemble into cellulose synthase complexes (CSCs). These complexes have been visualized as sixfold symmetrical rosettes by freeze-fracture electron microscopy (liu2023actomyosinandcsi1pom2 pages 1-2, gu2022cellbiologyof pages 1-2)
Trans-Golgi Network (TGN): CSCs are packaged into secretory vesicles for delivery to the plasma membrane (liu2023actomyosinandcsi1pom2 pages 1-2, gu2022cellbiologyof pages 1-2)
Small CESA Compartments (SmaCCs/MASCs): Recent research has identified a non-canonical delivery route where membrane patches from Golgi attach to cortical microtubules and stretch to generate small CESA-containing compartments that migrate along microtubules before fusing with the plasma membrane (liu2023actomyosinandcsi1pom2 pages 1-2)
Plasma Membrane: At the PM, CSCs are inserted as rosette structures (typically containing 18 CESA subunits organized as 6 trimers) that track bidirectionally along cortical microtubules during active cellulose synthesis (verma2023insightsintosubstrate pages 1-5, huang2023pointmutationsin pages 1-2, liu2023actomyosinandcsi1pom2 pages 1-2)
Several proteins facilitate CSC trafficking and localization (liu2023actomyosinandcsi1pom2 pages 1-2, gu2022cellbiologyof pages 1-2):
- STELLO (STL) proteins: Required for CSC assembly in the Golgi (liu2023actomyosinandcsi1pom2 pages 1-2)
- CSI1/POM2: Serves as a linker protein that connects CESAs to cortical microtubules and marks vesicle docking sites (liu2023actomyosinandcsi1pom2 pages 1-2)
- Actomyosin system: Myosin motors propel Golgi movement along actin filaments to facilitate membrane stretching and SmaCCs/MASCs formation (liu2023actomyosinandcsi1pom2 pages 1-2)
- Exocyst complex and PATROL1: Mediate tethering and fusion of CSC-containing vesicles to the plasma membrane (liu2023actomyosinandcsi1pom2 pages 1-2)
The primary biological function of cellulose synthase is the synthesis of cellulose, the main load-bearing polymer of plant cell walls (cosgrove2024structureandgrowth pages 1-4, gu2022cellbiologyof pages 1-2). Cellulose provides mechanical strength to the cell wall, enabling it to resist turgor pressure (typically 5-10 atmospheres) and maintain cell shape (cosgrove2024structureandgrowth pages 1-4).
Plant cells produce two types of cell walls (zhang2025cellulosesynthasetacesa7 pages 1-2):
- Primary cell wall (PCW): Synthesized during cell growth and expansion; in Arabidopsis, primary wall CSCs contain CESA1, CESA3, and CESA6-like proteins (huang2023pointmutationsin pages 1-2, zhang2025cellulosesynthasetacesa7 pages 1-2)
- Secondary cell wall (SCW): Deposited after cell expansion ceases, providing additional structural support; in Arabidopsis, secondary wall CSCs comprise CESA4, CESA7, and CESA8 (huang2023pointmutationsin pages 1-2, zhang2025cellulosesynthasetacesa7 pages 1-2)
Cellulose synthesis is intimately linked to cell growth through coordination with the cytoskeleton and wall loosening processes (cosgrove2024structureandgrowth pages 1-4, gu2022cellbiologyof pages 1-2). Growing walls must combine mechanical strength with dynamic extensibility to allow irreversible yielding (creep) in response to turgor pressure (cosgrove2024structureandgrowth pages 1-4).
The orientation of cellulose microfibrils, guided by cortical microtubules, influences the direction of cell expansion. CSCs track along cortical microtubules via the CSI1/POM2 linker protein, ensuring that cellulose deposition occurs in proper orientations to control cell shape (liu2023actomyosinandcsi1pom2 pages 1-2, gu2022cellbiologyof pages 1-2).
Cellulose and callose (ฮฒ-1,3-glucan) biosynthesis both utilize UDP-glucose as their substrate, creating metabolic competition (liu2024balancedcalloseand pages 1-2). During pathogen infection and plant immune responses, there is a negative correlation between cellulose and callose biosynthesis, as UDP-glucose is channeled toward callose deposition at infection sites (liu2024balancedcalloseand pages 1-2). The balance between these two biosynthetic processes is mediated by ฮฒ-1,3-glucanases such as BG2 (liu2024balancedcalloseand pages 1-2).
Cell wall modifications involving cellulose synthesis play crucial roles in plant defense responses (zhang2025cellulosesynthasetacesa7 pages 1-2, liu2024balancedcalloseand pages 1-2). Changes in cellulose biosynthesis can trigger cell wall integrity (CWI) sensing pathways that activate defense responses, including:
- Release of damage-associated molecular patterns (DAMPs)
- Activation of pathogenesis-related (PR) genes
- Enhanced lignin deposition
- Reactive oxygen species (ROS) accumulation
For example, silencing of wheat TaCESA7 led to restricted fungal hyphal spread, increased necrotic area, enhanced ROS accumulation, and promoted lignin synthesis, collectively improving resistance to stripe rust (Puccinia striiformis f. sp. tritici) (zhang2025cellulosesynthasetacesa7 pages 1-2).
Cellulose synthesis is regulated by multiple plant hormone signaling pathways (cosgrove2024structureandgrowth pages 1-4):
- Auxin: Rapidly stimulates wall acidification and promotes expansin-mediated wall loosening; also reorganizes cortical microtubule arrays to modify cellulose deposition direction (cosgrove2024structureandgrowth pages 1-4)
- Brassinosteroids: Influence wall growth and cellulose synthesis through intracellular signaling networks (cosgrove2024structureandgrowth pages 1-4)
- Ethylene: Induces cell wall thickening and upregulates expression of cellulose synthase genes, affecting cell wall establishment (cosgrove2024structureandgrowth pages 1-4)
- Gibberellin: Participates in developmental regulation of cell wall synthesis (cosgrove2024structureandgrowth pages 1-4)
In peanut specifically, transcriptomic studies have shown that plant hormones (IAA, GA, and brassinosteroids) regulate pod size by controlling cell wall biosynthesis genes, including those involved in cellulose synthesis, although A0A444Z7V7 was not specifically identified in those studies.
CESA proteins function as part of large multimeric complexes at the plasma membrane (verma2023insightsintosubstrate pages 1-5, huang2023pointmutationsin pages 1-2). Structural and genetic evidence indicates that each CSC rosette contains approximately 18 CESA subunits organized as 6 homotrimeric or heterotrimeric units (verma2023insightsintosubstrate pages 1-5, huang2023pointmutationsin pages 1-2). In wheat, TaCESA7 was observed to form dimers that subsequently assemble into larger CESA complexes (zhang2025cellulosesynthasetacesa7 pages 1-2).
The plant-conserved region (PCR) in CESA proteins creates an electropositive trimer interface through hydrophobic contacts, facilitating CESA trimerization (huang2023pointmutationsin pages 1-2). The cysteine-rich CSR domain is thought to facilitate membrane trafficking via S-acylation (huang2023pointmutationsin pages 1-2).
CSCs at the plasma membrane track along cortical microtubules through direct and indirect interactions (liu2023actomyosinandcsi1pom2 pages 1-2, gu2022cellbiologyof pages 1-2):
- CSI1/POM2: Binds both CESA proteins and microtubules, serving as a critical linker that guides CSC movement
- Microtubule organization: Proper microtubule organization is essential for positioning CSCs and determining cellulose microfibril orientation
- Actin cytoskeleton: Involved in trafficking of CSC-containing vesicles from the Golgi to the plasma membrane
Multiple proteins regulate CESA activity, trafficking, and complex formation (huang2023pointmutationsin pages 1-2, liu2023actomyosinandcsi1pom2 pages 1-2):
- STELLO family proteins: Required for CSC assembly in the Golgi
- Exocyst complex components: Facilitate vesicle tethering at the plasma membrane
- PATROL1: Interacts with CSI1/POM2 and exocyst subunits to facilitate CSC delivery
- Myosin XIK: Interacts with the exocyst complex to promote vesicle tethering
Recent structural biology advances have provided unprecedented insights into plant cellulose synthase function. Cryo-EM structures of poplar CesA8 have revealed substrate coordination mechanisms, showing how UDP-glucose binds to the catalytic pocket and how conserved gating loops position substrates for glycosyl transfer (verma2023insightsintosubstrate pages 1-5). Cell-free expression systems have enabled biochemical characterization of plant cellulose synthases, confirming their catalytic parameters and substrate requirements (jayachandran2024cellfreeexpressionand pages 1-5).
The trafficking pathway from ER to plasma membrane has been extensively mapped using live-cell imaging in Arabidopsis, revealing both canonical vesicle-mediated secretion and non-canonical membrane-stretching mechanisms for CSC delivery (liu2023actomyosinandcsi1pom2 pages 1-2, gu2022cellbiologyof pages 1-2).
Despite extensive knowledge of plant cellulose synthases generally, no experimental studies specifically characterize A0A444Z7V7 from peanut. The functional annotation provided in this report is based on:
Transcriptomic studies in peanut have identified differential expression of cell wall synthesis genes during pod development, including upregulation of cellulose synthesis-related genes during rapid growth stages. However, these studies do not specifically validate the function of A0A444Z7V7. Future research directions for this specific peanut protein include:
- Isoform-specific expression profiling across peanut tissues and developmental stages
- Determination of whether A0A444Z7V7 functions in primary or secondary wall synthesis
- Biochemical characterization of substrate affinity and catalytic parameters
- Functional validation through reverse genetics (CRISPR-mediated knockout or RNAi)
| Protein / field | Summary for A0A444Z7V7 (Arachis hypogaea) | Evidence basis |
|---|---|---|
| Protein name | Cellulose synthase domain-containing protein; UniProt accession A0A444Z7V7; ORF name Ahy_B05g078721; annotated in peanut (Arachis hypogaea) as a glycosyltransferase family 2 (GT2) protein with a cellulose synthase domain. | UniProt annotation provided by user; plant CESA/CSL proteins are GT2 enzymes with cellulose_synt domains (jayachandran2024cellfreeexpressionand pages 1-5, huang2023pointmutationsin pages 1-2) |
| Family classification | Most consistent with a plant cellulose synthase/cellulose synthase-like membrane glycosyltransferase in GT2. Conserved cellulose synthase-related proteins typically contain catalytic motifs and transmembrane segments; CESA proteins also commonly contain an N-terminal zinc-binding region. | GT2 family placement and cellulose synthase domain discussed for plant CesA proteins (jayachandran2024cellfreeexpressionand pages 1-5, huang2023pointmutationsin pages 1-2); plant cellulose synthase proteins are highly conserved and include zinc finger plus multiple TM domains (zhang2025cellulosesynthasetacesa7 pages 1-2) |
| Catalytic function | Inferred cellulose synthase-type activity: transfer of glucosyl residues from UDP-glucose to the non-reducing end of a nascent ฮฒ-1,4-glucan chain, thereby elongating cellulose and coupling polymerization to translocation across the membrane. | Recent structural/mechanistic studies of plant CesA8 and CESA6 (verma2023insightsintosubstrate pages 1-5, huang2023pointmutationsin pages 1-2) |
| Substrate specificity | Primary donor substrate is UDP-glucose (UDP-Glc); acceptor is the growing cellulose chain, specifically the C4 hydroxyl at the non-reducing end. Product release yields UDP. | Directly stated for plant cellulose synthase (verma2023insightsintosubstrate pages 1-5); shared UDP-glucose dependence of cellulose biosynthesis also noted in immune/cell wall studies (liu2024balancedcalloseand pages 1-2) |
| Km value | No peanut-specific kinetic measurement found for A0A444Z7V7. The best recent plant comparator is poplar PttCesA8, with reported Km = 295.8 ยตM for UDP-glucose in a reconstituted biochemical assay. This should be treated as a reference value, not a peanut-specific measurement. | Biochemical characterization of PttCesA8 (jayachandran2024cellfreeexpressionand pages 1-5) |
| Subcellular localization | Expected active site of function: plasma membrane, where cellulose synthase complexes synthesize cellulose at the cell surface. Biosynthetic route: synthesized in ER, assembled in Golgi into cellulose synthase complexes/rosettes, then trafficked via Golgi/TGN-derived compartments to the plasma membrane. | PM localization and trafficking from ER/Golgi to PM shown/reviewed for plant CESA proteins (huang2023pointmutationsin pages 1-2, liu2023actomyosinandcsi1pom2 pages 1-2, gu2022cellbiologyof pages 1-2); PM localization confirmed for wheat TaCESA7 (zhang2025cellulosesynthasetacesa7 pages 1-2) |
| Higher-order complex organization | Likely functions as part of a multimeric cellulose synthase complex (CSC), commonly described as a sixfold rosette at the plasma membrane, with ~18 CESA subunits in Arabidopsis/poplar models. | Rosette CSC organization and trafficking evidence (huang2023pointmutationsin pages 1-2, liu2023actomyosinandcsi1pom2 pages 1-2) |
| Biological processes | Cell wall cellulose deposition; primary and/or secondary cell wall biogenesis; cell growth and morphogenesis; mechanical reinforcement of the wall; likely contribution to developmental processes requiring wall expansion or strengthening. | Cellulose is the main load-bearing wall polymer and central to growth/development (huang2023pointmutationsin pages 1-2, cosgrove2024structureandgrowth pages 1-4, gu2022cellbiologyof pages 1-2) |
| Pathway involvement | Cellulose biosynthesis pathway within cell wall biogenesis; integrated with UDP-glucose metabolism; coordinated with cytoskeleton-guided wall assembly; functionally linked to cell wall integrity and remodeling pathways. | Cell wall biogenesis and cellulose synthesis reviews/mechanistic studies (liu2024balancedcalloseand pages 1-2, cosgrove2024structureandgrowth pages 1-4, gu2022cellbiologyof pages 1-2) |
| Relationship to other wall polymers | Cellulose biosynthesis shares UDP-glucose supply with callose biosynthesis, and changes in cellulose production can alter wall composition and defense-associated remodeling. | Antagonistic/balanced cellulose-callose relationship in immunity (liu2024balancedcalloseand pages 1-2) |
| Key molecular interactions | Interacts with other CESA subunits in CSCs; CSC guidance depends on cortical microtubules via CSI1/POM2; trafficking from Golgi involves STELLO proteins, actomyosin, SmaCCs/MASCs, and secretory machinery. Catalytic motifs (DDG, DXD, TED, QXXRW) are critical for activity, complex formation, and trafficking. | CESA complex assembly and catalytic-domain requirements (huang2023pointmutationsin pages 1-2); Golgi-to-PM delivery and CSI1/POM2 linkage (liu2023actomyosinandcsi1pom2 pages 1-2) |
| Regulation / signaling connections | Cellulose synthesis is influenced by developmental and stress signaling, including auxin and brassinosteroid effects on wall growth, and by cell wall integrity/defense signaling during pathogen responses. | Hormone and wall-growth regulation review (cosgrove2024structureandgrowth pages 1-4); defense/cell wall integrity links (zhang2025cellulosesynthasetacesa7 pages 1-2, liu2024balancedcalloseand pages 1-2) |
| Peanut-specific evidence | No direct experimental paper was found for A0A444Z7V7 itself. Peanut transcriptomic studies report altered expression of cellulose synthesis/cell wall genes during pod development, consistent with a role for cellulose-related genes in peanut growth, but they do not specifically validate A0A444Z7V7. | Peanut transcriptome studies summarized earlier in conversation; mechanistic inference relies on conserved plant CESA literature (huang2023pointmutationsin pages 1-2, cosgrove2024structureandgrowth pages 1-4) |
| Confidence assessment | Moderate for broad function/localization/pathway assignment based on strong cross-species conservation of plant cellulose synthases; low for peanut-specific isoform details such as exact wall type specificity, expression domain, and kinetics because A0A444Z7V7 lacks direct experimental characterization. | Cross-species structural, biochemical, and cell-biological evidence for plant CESA proteins (jayachandran2024cellfreeexpressionand pages 1-5, verma2023insightsintosubstrate pages 1-5, huang2023pointmutationsin pages 1-2, liu2023actomyosinandcsi1pom2 pages 1-2, gu2022cellbiologyof pages 1-2) |
Table: This table summarizes the most likely function, localization, pathway context, and interaction partners of the peanut protein A0A444Z7V7 by integrating its UniProt/domain annotation with recent plant cellulose synthase literature. It is useful because direct peanut-specific evidence is limited, so the report must rely on well-supported cross-species inference.
The gene A0A444Z7V7 from Arachis hypogaea encodes a cellulose synthase domain-containing protein that, based on strong evolutionary conservation and domain architecture, functions as a cellulose synthase enzyme. The protein catalyzes the synthesis of ฮฒ-1,4-glucan (cellulose) chains from UDP-glucose at the plasma membrane, where it assembles into large multimeric complexes that track along cortical microtubules.
This enzyme plays essential roles in:
- Cell wall biosynthesis: Providing the main structural polymer for mechanical support
- Cell growth and morphogenesis: Controlling cell shape through oriented cellulose deposition
- Plant defense: Contributing to cell wall integrity and pathogen resistance
- Metabolic integration: Participating in UDP-glucose metabolism pathways
While direct experimental characterization of A0A444Z7V7 is lacking, the high degree of structural and functional conservation among plant cellulose synthases allows confident functional annotation based on extensive recent literature from model plant species. Future experimental validation in peanut would strengthen understanding of this protein's specific roles in peanut development, pod formation, and stress responses.
All major findings in this report are supported by recent authoritative literature (2022-2025):
- Structural and mechanistic studies: pqac-00000000, pqac-00000001
- Trafficking and localization: pqac-00000007, pqac-00000008
- Catalytic mechanisms: pqac-00000002
- Defense and cell wall integrity: pqac-00000003, pqac-00000004
- Cell wall biology and growth: pqac-00000005
Publication dates: Jayachandran et al. 2024; Verma et al. 2023; Huang et al. 2023; Zhang et al. 2025; Liu et al. 2024; Cosgrove 2024; Liu et al. 2023; Gu and Rasmussen 2022.
References
(jayachandran2024cellfreeexpressionand pages 1-5): Dharanidaran Jayachandran, Amar D. Parvate, Jory T. Brookreson, James E. Evans, and Shishir P.S. Chundawat. Cell-free expression and biochemical characterization of polysaccharide-synthesizing glycosyltransferases. bioRxiv, Feb 2024. URL: https://doi.org/10.1101/2024.02.12.580006, doi:10.1101/2024.02.12.580006. This article has 1 citations.
(verma2023insightsintosubstrate pages 1-5): Preeti Verma, Albert L. Kwansa, Ruoya Ho, Yaroslava G. Yingling, and Jochen Zimmer. Insights into substrate coordination and glycosyl transfer of poplar cellulose synthase-8. Structure (London, England : 1993), 31:1166-1173.e6, Aug 2023. URL: https://doi.org/10.1016/j.str.2023.07.010, doi:10.1016/j.str.2023.07.010. This article has 22 citations.
(huang2023pointmutationsin pages 1-2): Lei Huang, Weiwei Zhang, Xiaohui Li, Christopher J Staiger, and Chunhua Zhang. Point mutations in the catalytic domain disrupt cellulose synthase (cesa6) vesicle trafficking and protein dynamics. The Plant Cell, 35:2654-2677, Apr 2023. URL: https://doi.org/10.1093/plcell/koad110, doi:10.1093/plcell/koad110. This article has 15 citations.
(zhang2025cellulosesynthasetacesa7 pages 1-2): Yanqin Zhang, Longhui Yu, Shuangyuan Guo, Xueling Huang, Yihan Chen, Pengfei Gan, Yi lin, Xiaojie Wang, Zhensheng Kang, and Xinmei Zhang. Cellulose synthase tacesa7 negatively regulates wheat resistance to stripe rust by reducing cell wall lignification. Stress Biology, Jun 2025. URL: https://doi.org/10.1007/s44154-025-00244-7, doi:10.1007/s44154-025-00244-7. This article has 6 citations.
(liu2024balancedcalloseand pages 1-2): Xiaolin Liu, Zhiming Ma, Tuan Minh Tran, Carsten Rautengarten, Yingying Cheng, Liang Yang, Berit Ebert, Staffan Persson, and Yansong Miao. Balanced callose and cellulose biosynthesis in arabidopsis quorum-sensing signaling and pattern-triggered immunity. Plant Physiology, 194:137-152, Aug 2024. URL: https://doi.org/10.1093/plphys/kiad473, doi:10.1093/plphys/kiad473. This article has 16 citations and is from a highest quality peer-reviewed journal.
(cosgrove2024structureandgrowth pages 1-4): Daniel J. Cosgrove. Structure and growth of plant cell walls. Nature reviews. Molecular cell biology, 25:340-358, Dec 2024. URL: https://doi.org/10.1038/s41580-023-00691-y, doi:10.1038/s41580-023-00691-y. This article has 421 citations.
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id: A0A444Z7V7
gene_symbol: A0A444Z7V7
product_type: PROTEIN
status: DRAFT
taxon:
id: NCBITaxon:3818
label: Arachis hypogaea
description: >-
Cellulose synthase-like protein D3 (CSLD3) from Arachis hypogaea, a member of the
glycosyltransferase family 2 (GT2) within the plant cellulose synthase-like D (CSLD)
subfamily. The protein contains a cellulose synthase domain (PF03552), an N-terminal zinc
finger RING domain, and multiple transmembrane helices consistent with integral membrane
glycosyltransferase topology. CSLD proteins use GDP-mannose or UDP-glucose as donor
substrates to synthesize beta-1,4-linked mannan or glucomannan polysaccharides that are
components of hemicellulose in plant cell walls. In Arabidopsis, CSLD3 orthologs function
at sites of rapid polarized cell wall deposition such as root hair tips, pollen tubes, and
during cell plate formation. The protein is synthesized in the ER, assembled in the Golgi
apparatus, and trafficked to the plasma membrane where it catalyzes polysaccharide
biosynthesis. No direct experimental characterization exists for this specific peanut
protein; functional annotation is inferred from conserved domain architecture and extensive
characterization of CSLD orthologs in model plants.
existing_annotations:
- term:
id: GO:0000139
label: Golgi membrane
evidence_type: IEA
original_reference_id: GO_REF:0000044
qualifier: located_in
review:
summary: >-
Golgi membrane localization is consistent with the biosynthetic trafficking route of
CSLD proteins. CESA/CSLD proteins are synthesized in the ER, assembled into complexes
in the Golgi, and trafficked to the plasma membrane. The Golgi is a transit compartment
rather than the primary site of function.
action: ACCEPT
reason: >-
UniProt subcellular location annotation places this protein at the Golgi apparatus
membrane as a multi-pass membrane protein, consistent with CSLD protein biology. The
Golgi is where CSL protein complexes are assembled before delivery to the plasma membrane.
supported_by:
- reference_id: file:ARAHY/A0A444Z7V7/A0A444Z7V7-uniprot.txt
supporting_text: >-
SUBCELLULAR LOCATION: Golgi apparatus membrane
- reference_id: file:ARAHY/A0A444Z7V7/A0A444Z7V7-deep-research-falcon.md
supporting_text: >-
Individual CESA proteins are transported to the Golgi, where they assemble into
cellulose synthase complexes
- term:
id: GO:0005737
label: cytoplasm
evidence_type: IEA
original_reference_id: GO_REF:0000117
qualifier: located_in
review:
summary: >-
Cytoplasm is an overly broad localization for this integral membrane protein. The
protein traverses membranes with multiple transmembrane helices and its catalytic domain
faces the cytoplasmic side, but calling it a cytoplasmic protein is misleading. More
specific terms (Golgi membrane, plasma membrane, endomembrane system) are already
annotated.
action: MARK_AS_OVER_ANNOTATED
reason: >-
ARBA-derived annotation. While the catalytic domain is cytoplasm-facing, the protein
is an integral membrane glycosyltransferase with 7 predicted transmembrane helices.
Calling it cytoplasmic is uninformative given that more specific membrane localizations
are already annotated.
- term:
id: GO:0009409
label: response to cold
evidence_type: IEA
original_reference_id: GO_REF:0000117
qualifier: involved_in
review:
summary: >-
Response to cold is a pleiotropic stress annotation with no clear mechanistic connection
to cellulose synthase-like protein function. While cell wall remodeling genes can be
transcriptionally responsive to cold stress in plants, this does not establish that
cold response is a core or even direct function of this protein. ARBA rules often
propagate broad stress-response annotations based on expression patterns in distantly
related species.
action: MARK_AS_OVER_ANNOTATED
reason: >-
ARBA-derived annotation. Cold-responsive transcriptional changes in cell wall genes are
a secondary consequence of stress-induced growth adjustments, not a direct molecular
function of this glycosyltransferase. No specific evidence links CSLD3-type proteins to
cold stress response pathways.
- term:
id: GO:0012505
label: endomembrane system
evidence_type: IEA
original_reference_id: GO_REF:0000117
qualifier: located_in
review:
summary: >-
Endomembrane system is a correct but very broad localization. The protein transits
through the ER and Golgi (parts of the endomembrane system) during biosynthesis and
trafficking to the plasma membrane. This annotation is subsumed by the more specific
Golgi membrane annotation.
action: KEEP_AS_NON_CORE
reason: >-
ARBA-derived annotation. Technically correct since the Golgi is part of the
endomembrane system, but redundant with the more specific GO:0000139 (Golgi membrane)
annotation.
- term:
id: GO:0016020
label: membrane
evidence_type: IEA
original_reference_id: GO_REF:0000002
qualifier: located_in
review:
summary: >-
Membrane is a very broad localization. The protein is clearly an integral membrane
protein with multiple transmembrane helices, but this generic annotation is subsumed
by more specific membrane annotations (Golgi membrane).
action: KEEP_AS_NON_CORE
reason: >-
InterPro-derived annotation from the cellulose synthase domain (IPR005150). Correct but
uninformative given more specific membrane annotations already present.
- term:
id: GO:0016760
label: cellulose synthase (UDP-forming) activity
evidence_type: IEA
original_reference_id: GO_REF:0000002
qualifier: enables
review:
summary: >-
This annotation derives from the InterPro cellulose synthase domain (IPR005150), which
covers the entire CESA/CSL superfamily. However, this protein belongs to the CSLD
(cellulose synthase-like D) subfamily, not the true CESA subfamily. CSLD proteins have
been shown to have mannan synthase and glucomannan synthase activities rather than
(or in addition to) cellulose synthase activity. The InterPro2GO mapping is overly
specific for CSLD subfamily members. A more appropriate annotation would be
beta-1,4-mannan synthase activity or a more general transferase activity term.
action: MODIFY
reason: >-
The protein is classified in the plant cellulose synthase-like D subfamily per UniProt.
CSLD proteins synthesize mannans and glucomannans rather than cellulose. The cellulose
synthase (UDP-forming) activity term is a mis-annotation arising from the broad
IPR005150 domain covering the entire CESA/CSL superfamily.
proposed_replacement_terms:
- id: GO:0051753
label: mannan synthase activity
- term:
id: GO:0030244
label: cellulose biosynthetic process
evidence_type: IEA
original_reference_id: GO_REF:0000002
qualifier: involved_in
review:
summary: >-
Like the cellulose synthase activity annotation, this process annotation derives from
the broad IPR005150 domain mapping. CSLD subfamily proteins are involved in mannan and
glucomannan biosynthesis rather than cellulose biosynthesis per se. While CSLD proteins
contribute to cell wall biosynthesis, the specific process is hemicellulose (mannan)
synthesis, not cellulose synthesis.
action: MODIFY
reason: >-
CSLD proteins synthesize mannans/glucomannans, which are hemicellulose components, not
cellulose. A more appropriate process term would be mannan biosynthetic process or cell
wall organization.
proposed_replacement_terms:
- id: GO:0071555
label: cell wall organization
- term:
id: GO:0051753
label: mannan synthase activity
evidence_type: IEA
original_reference_id: GO_REF:0000117
qualifier: enables
review:
summary: >-
Mannan synthase activity is the most appropriate molecular function annotation for a
CSLD subfamily protein. CSLD proteins use GDP-mannose as a donor substrate to synthesize
beta-1,4-mannan polysaccharides, which are hemicellulose components of the plant cell
wall. This ARBA-derived annotation correctly captures the enzymatic activity of CSLD
proteins.
action: ACCEPT
reason: >-
CSLD subfamily proteins have been experimentally shown to possess mannan synthase
activity in multiple plant species. This is consistent with the protein being classified
in the plant cellulose synthase-like D subfamily.
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with GO terms
findings:
- statement: >-
GO_REF:0000002 supplied InterPro-derived annotations for cellulose synthase activity,
cellulose biosynthetic process, and membrane localization based on the IPR005150
cellulose synthase domain.
- id: GO_REF:0000044
title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary
mapping, accompanied by conservative changes to GO terms applied by UniProt
findings:
- statement: >-
GO_REF:0000044 supplied the Golgi membrane localization annotation based on UniProt
subcellular location vocabulary.
- id: GO_REF:0000117
title: Electronic Gene Ontology annotations created by ARBA machine learning models
findings:
- statement: >-
GO_REF:0000117 supplied ARBA-derived annotations for cytoplasm localization, response
to cold, endomembrane system localization, and mannan synthase activity.
- id: file:ARAHY/A0A444Z7V7/A0A444Z7V7-uniprot.txt
title: UniProtKB entry for A0A444Z7V7
findings:
- statement: >-
UniProt classifies this protein in the glycosyltransferase 2 family, plant cellulose
synthase-like D subfamily, with Golgi apparatus membrane localization and a cellulose
synthase domain (PF03552) plus zinc finger RING domain (PF14570).
- id: file:ARAHY/A0A444Z7V7/A0A444Z7V7-goa.tsv
title: QuickGO GOA annotations for A0A444Z7V7
findings:
- statement: GOA rows supplied the 8 existing annotations reviewed in this file.
- id: file:ARAHY/A0A444Z7V7/A0A444Z7V7-deep-research-falcon.md
title: Deep research report on A0A444Z7V7 cellulose synthase domain-containing protein
findings:
- statement: >-
Deep research confirmed no direct experimental studies exist for A0A444Z7V7 from
peanut. Functional inference relies on conserved domain architecture and
characterization of homologous CESA/CSL proteins in Arabidopsis, poplar, wheat, and
other model plants.
core_functions:
- description: >-
Mannan synthase activity at the Golgi or plasma membrane, catalyzing the synthesis of
beta-1,4-mannan polysaccharides from GDP-mannose for incorporation into hemicellulose
in the plant cell wall. Functions as part of cell wall organization during polarized
growth processes.
molecular_function:
id: GO:0051753
label: mannan synthase activity
directly_involved_in:
- id: GO:0071555
label: cell wall organization
locations:
- id: GO:0000139
label: Golgi membrane
supported_by:
- reference_id: file:ARAHY/A0A444Z7V7/A0A444Z7V7-uniprot.txt
supporting_text: >-
Belongs to the glycosyltransferase 2 family. Plant cellulose synthase-like D subfamily
- reference_id: file:ARAHY/A0A444Z7V7/A0A444Z7V7-deep-research-falcon.md
supporting_text: >-
cellulose synthase domain-containing protein belonging to the glycosyltransferase
family 2 (GT2)