id: Q1G3K8 gene_symbol: RIC7 product_type: PROTEIN status: DRAFT taxon: id: NCBITaxon:3702 label: Arabidopsis thaliana description: RIC7 is a CRIB-domain effector of plant ROP small GTPases. It binds activated ROP1 and ROP2 and is recruited to the plasma membrane during signaling. In guard cells it restrains light-induced stomatal opening through a pathway involving the exocyst component Exo70B1. RIC7 also attenuates ABA-induced stomatal closure, with elevated RIC7 expression associated with reduced guard-cell ROS accumulation. The protein occupies nuclear, cytoplasmic and peripheral plasma-membrane pools, with its distribution depending on light and ROP activation. RIC7 also interacts with ROP1 in pollen-tube signaling; heterologous overexpression reduces pollen-tube elongation. existing_annotations: - term: id: GO:0003674 label: molecular_function evidence_type: ND original_reference_id: GO_REF:0000015 qualifier: enables review: summary: RIC7 binds activated ROP small GTPases; its molecular function is experimentally characterized. action: MODIFY reason: 'The ND root annotation does not capture the ROP-effector activity. Prefer small GTPase binding (GO:0031267): Jeon et al. demonstrate preferential binding to GTP-loaded ROP2 in Figure 7D (PMID:18178769), and Wu et al. report ROP1 interaction (PMID:11752391).' supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt record_section: ["CC:SUBUNIT"] supporting_text: Interacts with ARAC4/ROP2 and ARAC11/ROP1. additional_reference_ids: - PMID:18178769 - PMID:11752391 proposed_replacement_terms: - id: GO:0031267 label: small GTPase binding nd_case: STALE - term: id: GO:0005634 label: nucleus evidence_type: IDA original_reference_id: PMID:18178769 qualifier: located_in review: summary: RIC7 accumulates in guard-cell nuclei in darkness. action: KEEP_AS_NON_CORE reason: GFP-RIC7 imaging supports nuclear localization under dark or inactive-ROP2 conditions (PMID:18178769, Figure 7). Retain this conditional location; a specific nuclear activity has not been established. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt record_section: ["CC:SUBCELLULAR LOCATION"] supporting_text: 'In guard cells in the CC dark localizes predominantly in the nucleus' - term: id: GO:0005634 label: nucleus evidence_type: IEA original_reference_id: GO_REF:0000044 qualifier: located_in supporting_entities: - UniProtKB-SubCell:SL-0191 review: summary: The nuclear-location mapping agrees with experimentally observed dark-state localization. action: KEEP_AS_NON_CORE reason: The Swiss-Prot location maps to a real RIC7 pool documented in PMID:18178769. It does not imply a constitutive nuclear role or transcriptional activity. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt record_section: ["CC:SUBCELLULAR LOCATION"] supporting_text: 'In guard cells in the CC dark localizes predominantly in the nucleus' additional_reference_ids: - PMID:18178769 - term: id: GO:0005634 label: nucleus evidence_type: ISM original_reference_id: GO_REF:0000122 qualifier: located_in review: summary: The nuclear prediction is consistent with the observed nuclear pool of RIC7. action: KEEP_AS_NON_CORE reason: Nuclear localization is independently supported by GFP-RIC7 imaging in PMID:18178769. The AtSubP prediction is compatible with that conditional distribution, although it cannot describe light-dependent redistribution. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt record_section: ["CC:SUBCELLULAR LOCATION"] supporting_text: 'In guard cells in the CC dark localizes predominantly in the nucleus' additional_reference_ids: - PMID:18178769 - term: id: GO:0005737 label: cytoplasm evidence_type: EXP original_reference_id: PMID:11752391 qualifier: located_in review: summary: RIC7 has a cytoplasmic pool in pollen tubes. action: ACCEPT reason: The RIC7 localization experiments in PMID:11752391 support a soluble intracellular pool alongside membrane-associated protein. This distribution is compatible with recruitment of a CRIB-containing ROP effector. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt supporting_text: 'Cytoplasm CC {ECO:0000269|PubMed:11752391, ECO:0000269|PubMed:18178769}.' - term: id: GO:0005737 label: cytoplasm evidence_type: EXP original_reference_id: PMID:18178769 qualifier: located_in review: summary: RIC7 occurs in the guard-cell cytoplasm following illumination. action: ACCEPT reason: The cytoplasmic pool accompanies light-dependent redistribution in the ROP2 experiments (PMID:18178769); it is consistent with a soluble effector that can be recruited to the plasma membrane. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt supporting_text: 'Cytoplasm CC {ECO:0000269|PubMed:11752391, ECO:0000269|PubMed:18178769}.' - term: id: GO:0005737 label: cytoplasm evidence_type: IEA original_reference_id: GO_REF:0000044 qualifier: located_in supporting_entities: - UniProtKB-SubCell:SL-0086 review: summary: The cytoplasm mapping reflects an experimentally supported RIC7 location. action: ACCEPT reason: Swiss-Prot curates cytoplasmic localization from PMID:11752391 and PMID:18178769. This is consistent with the protein's dynamic intracellular distribution. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt supporting_text: 'Cytoplasm CC {ECO:0000269|PubMed:11752391, ECO:0000269|PubMed:18178769}.' additional_reference_ids: - PMID:11752391 - PMID:18178769 - term: id: GO:0005886 label: plasma membrane evidence_type: EXP original_reference_id: PMID:11752391 qualifier: located_in review: summary: RIC7 associates with the pollen-tube plasma membrane. action: ACCEPT reason: The localization experiments in PMID:11752391 support membrane recruitment of RIC7 during ROP signaling. Membrane association is peripheral rather than evidence for an integral membrane receptor. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt supporting_text: 'Cell CC membrane {ECO:0000269|PubMed:11752391, ECO:0000269|PubMed:18178769};' - term: id: GO:0005886 label: plasma membrane evidence_type: IBA original_reference_id: GO_REF:0000033 qualifier: is_active_in supporting_entities: - AGI_LocusCode:AT2G20430 - AGI_LocusCode:AT4G28556 - PANTHER:PTN005297055 review: summary: Plasma-membrane association is consistent with the inherited RIC-family effector role. action: ACCEPT reason: The PAINT inference at PANTHER:PTN005297055 agrees with target-specific localization in PMID:11752391 and PMID:18178769. There is no target-specific evidence against inheritance of this location. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt supporting_text: 'Cell CC membrane {ECO:0000269|PubMed:11752391, ECO:0000269|PubMed:18178769};' additional_reference_ids: - PMID:11752391 - PMID:18178769 - term: id: GO:0005886 label: plasma membrane evidence_type: IDA original_reference_id: PMID:18178769 qualifier: located_in review: summary: Activated ROP2 recruits RIC7 to the guard-cell plasma membrane. action: ACCEPT reason: Figure 7 of PMID:18178769 directly documents membrane recruitment following illumination or expression of constitutively active ROP2. This location is central to RIC7 signaling. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt supporting_text: 'Cell CC membrane {ECO:0000269|PubMed:11752391, ECO:0000269|PubMed:18178769};' - term: id: GO:0005886 label: plasma membrane evidence_type: IEA original_reference_id: GO_REF:0000120 qualifier: located_in supporting_entities: - ARBA:ARBA00027801 - UniProtKB-SubCell:SL-0039 review: summary: The electronic plasma-membrane annotation agrees with experimental localization. action: ACCEPT reason: The target-specific experiments in PMID:11752391 and PMID:18178769 demonstrate plasma-membrane association and support this electronic annotation. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt supporting_text: 'Cell CC membrane {ECO:0000269|PubMed:11752391, ECO:0000269|PubMed:18178769};' additional_reference_ids: - PMID:11752391 - PMID:18178769 - term: id: GO:0009416 label: response to light stimulus evidence_type: IDA original_reference_id: PMID:18178769 qualifier: acts_upstream_of_or_within review: summary: RIC7 participates in the guard-cell response to light. action: KEEP_AS_NON_CORE reason: The RIC7 experiments in PMID:18178769 show light-dependent redistribution and inhibition of light-induced stomatal opening. Retain this broad response as non-core; negative regulation of stomatal opening describes the physiological role more precisely. Redistribution supports responsiveness to light without establishing direct photoreception. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt record_section: ["CC:FUNCTION"] supporting_text: 'involved in the prevention of excessive stomatal opening upon light CC stimulation.' - term: id: GO:0009860 label: pollen tube growth evidence_type: IBA original_reference_id: GO_REF:0000033 qualifier: involved_in supporting_entities: - AGI_LocusCode:AT1G04450 - AGI_LocusCode:AT2G20430 - AGI_LocusCode:AT2G33460 - AGI_LocusCode:AT3G23380 - AGI_LocusCode:AT4G04900 - PANTHER:PTN008200783 review: summary: RIC7 participates in ROP-dependent pollen-tube growth regulation. action: KEEP_AS_NON_CORE reason: The PAINT inference at PANTHER:PTN008200783 is consistent with ROP1 binding, pollen expression and the heterologous overexpression phenotype in PMID:11752391. Retain the process without assigning an endogenous inhibitory mechanism from overexpression alone; stomatal regulation has stronger target-specific genetic support. supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt record_section: ["CC:MISCELLANEOUS"] supporting_text: 'Over-expression of RIC7 in tobacco germinating pollen CC reduces pollen tube elongation.' additional_reference_ids: - PMID:11752391 - PMID:26451971 - term: id: GO:0009966 label: regulation of signal transduction evidence_type: IBA original_reference_id: GO_REF:0000033 qualifier: involved_in supporting_entities: - AGI_LocusCode:AT1G04450 - PANTHER:PTN008706952 review: summary: RIC7 mediates downstream ROP signaling. action: ACCEPT reason: The inference at PANTHER:PTN008706952 is consistent with the experimentally characterized ROP-effector role. RIC7 binds ROP1/ROP2 and links activated ROP2 to control of stomatal movement (PMID:11752391; PMID:18178769; PMID:26451971). supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt record_section: ["CC:FUNCTION"] supporting_text: 'Functions as a downstream effector of Rho-related GTP binding CC proteins of the ''Rho of Plants'' (ROPs) family.' additional_reference_ids: - PMID:11752391 - PMID:18178769 - PMID:26451971 - term: id: GO:1902457 label: negative regulation of stomatal opening evidence_type: IMP original_reference_id: PMID:26451971 review: summary: RIC7 restrains light-induced stomatal opening. action: NEW reason: Arabidopsis ric7 loss-of-function, native-promoter complementation and overexpression establish a negative effect on stomatal opening (PMID:26451971). This captures the direction of the genetically demonstrated response. supported_by: - reference_id: PMID:26451971 supporting_text: Light-induced stomatal opening was promoted by ric7 knockout, whereas it was inhibited by RIC7 overexpression - term: id: GO:0090333 label: regulation of stomatal closure evidence_type: IMP original_reference_id: PMID:33586611 review: summary: Elevated RIC7 expression attenuates ABA-induced stomatal closure. action: NEW reason: The ric7-2 and ric7-3 promoter-insertion lines increase RIC7 expression and show reduced ABA-induced closure (PMID:33586611), consistent with the independent genetic evidence in PMID:26451971. The effect is negative; the available regulation term captures participation without treating these lines as knockouts or assigning a direct ROS-generating activity. additional_reference_ids: - PMID:26451971 supported_by: - reference_id: PMID:33586611 supporting_text: using two RIC7 overexpressing mutants, we confirmed the negative role of RIC7 in ABA-induced stomatal closure references: - id: GO_REF:0000015 title: Use of the ND evidence code for Gene Ontology (GO) terms findings: [] - id: GO_REF:0000033 title: Annotation inferences using phylogenetic trees findings: [] - 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: [] - id: GO_REF:0000120 title: Combined Automated Annotation using Multiple IEA Methods findings: [] - id: GO_REF:0000122 title: AtSubP analysis findings: [] - id: PMID:11752391 title: A genome-wide analysis of Arabidopsis Rop-interactive CRIB motif-containing proteins that act as Rop GTPase targets. findings: - statement: RIC7 interacts with active ROP1, associates with pollen-tube plasma membrane and cytoplasm, and affects tube elongation when expressed in tobacco pollen. reference_review: relevance: HIGH correctness: VERIFIED review_notes: PubMed title/DOI checked. Indexed full-text results and Table 4 examined; the published primers map to AT4G28556. Exact construct boundaries remain to be reconstructed. - id: PMID:18178769 title: The Arabidopsis small G protein ROP2 is activated by light in guard cells and inhibits light-induced stomatal opening. findings: - statement: RIC7 binds active ROP2 and undergoes light- and ROP-dependent redistribution in guard cells. reference_review: relevance: HIGH correctness: VERIFIED review_notes: PubMed title/DOI checked. Indexed full-text Figure 7 and Results directly assay RIC7 despite the ROP2-focused abstract, and the article specifies AT4G28556. - id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt title: 'UniProt Q1G3K8: CRIB domain-containing protein RIC7 (AT4G28556)' findings: - statement: The 216-residue protein contains a CRIB domain and interacts with ROP1 and ROP2. - id: PMID:26451971 title: The ROP2-RIC7 pathway negatively regulates light-induced stomatal opening by inhibiting exocyst subunit Exo70B1 in Arabidopsis. findings: - statement: RIC7 restrains light-induced stomatal opening in Arabidopsis. supporting_text: Light-induced stomatal opening was promoted by ric7 knockout, whereas it was inhibited by RIC7 overexpression reference_review: relevance: HIGH correctness: VERIFIED review_notes: PubMed title/DOI verified; mutant and complementation results support stomatal regulation. Published RT-PCR primers map to the AT4G28556 transcript in the accompanying analysis. - id: file:ARATH/Q1G3K8/Q1G3K8-bioinformatics/RESULTS.md title: RIC7 sequence identity and experimental primer mapping reference_review: relevance: HIGH correctness: VERIFIED review_notes: >- Re-read the sequence-identity and primer-mapping report; it directly supports assignment of the published RIC7 primers and cDNA to the AT4G28556/Q1G3K8 CRIB-protein locus. findings: - statement: Published RIC7 primers from Wu and Hong match the AT4G28556 transcript, and Q1G3K8 matches its RefSeq protein and DQ487576 CDS translation. - id: PMID:33586611 title: RIC7 plays a negative role in ABA-induced stomatal closure by inhibiting H(2)O(2) production. findings: - statement: RIC7 overexpression attenuates ABA-induced stomatal closure and is associated with lower guard-cell ROS accumulation. supporting_text: using two RIC7 overexpressing mutants, we confirmed the negative role of RIC7 in ABA-induced stomatal closure reference_review: relevance: HIGH correctness: VERIFIED review_notes: Full text and PubMed metadata examined. Both RIC7 qRT-PCR primers match AT4G28556 exactly. Promoter-insertion lines increase expression; they are not loss-of-function alleles. The phenotypes do not establish direct ROS enzymatic activity or transcriptional regulation by RIC7. core_functions: - description: Binds activated ROP small GTPases to regulate guard-cell movements, restraining light-induced stomatal opening through Exo70B1 and attenuating ABA-induced stomatal closure. molecular_function: id: GO:0031267 label: small GTPase binding directly_involved_in: - id: GO:1902457 label: negative regulation of stomatal opening - id: GO:0090333 label: regulation of stomatal closure locations: - id: GO:0005886 label: plasma membrane - id: GO:0005737 label: cytoplasm supported_by: - reference_id: file:ARATH/Q1G3K8/Q1G3K8-uniprot.txt record_section: ["CC:SUBUNIT"] supporting_text: Interacts with ARAC4/ROP2 and ARAC11/ROP1. - reference_id: PMID:26451971 supporting_text: Light-induced stomatal opening was promoted by ric7 knockout, whereas it was inhibited by RIC7 overexpression - reference_id: PMID:33586611 supporting_text: using two RIC7 overexpressing mutants, we confirmed the negative role of RIC7 in ABA-induced stomatal closure suggested_questions: - question: Does the nuclear pool of RIC7 have a biochemical function, or serve primarily as a regulated reservoir for membrane recruitment? - question: What endogenous pollen-tube phenotype follows specific loss of AT4G28556, and how does it relate to the heterologous overexpression phenotype? suggested_experiments: - hypothesis: ROP-dependent redistribution of endogenous RIC7 controls its access to Exo70B1. description: Introduce a functional fluorescent tag at the endogenous AT4G28556 locus and measure localization and Exo70B1 association during light transitions, using stomatal-aperture rescue to verify tag functionality. experiment_type: Endogenous tagging, live-cell imaging and functional complementation - hypothesis: AT4G28556 contributes to pollen-tube growth at physiological expression levels. description: Measure pollen germination, tube elongation and fertility in an AT4G28556-specific loss-of-function line and native-promoter rescue, verifying that adjacent AT4G28560 expression is preserved. experiment_type: Targeted genetics and pollen phenotyping