PIN1

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0005886 plasma membrane	IEA GO_REF:0000044	ACCEPT	Summary: PIN1 is an integral plasma-membrane auxin efflux carrier; the plasma membrane is its functional location. This UniProt subcellular-location mapping is fully consistent with experimental evidence. Reason: The plasma membrane is the bona fide functional compartment of PIN1, confirmed by multiple experimental studies; this is a core localization. Supporting Evidence: PMID:33705718 PINs, MAB4/MELs, and AGC kinases interact in the same complex at the plasma membrane.
GO:0016020 membrane	IEA GO_REF:0000002	MODIFY	Summary: Generic membrane localization from InterPro mapping. PIN1 is a multi-pass membrane protein, so the term is correct but far less informative than the plasma-membrane annotation. Reason: The integral membrane claim is correct; direct imaging establishes plasma membrane as the principal transport compartment. Refine the broad membrane term without denying intracellular trafficking pools. Proposed replacements: plasma membrane Supporting Evidence: PMID:35917925 The transmembrane domain of PIN1 has ten transmembrane segments (TM1 to TM10), with both N and C termini located extracellularly
GO:0055085 transmembrane transport	IEA GO_REF:0000002	MODIFY	Summary: PIN1 mediates transmembrane transport of auxin across the plasma membrane. The term is correct but is a broad parent of the more specific auxin export and polar auxin transport terms. Reason: Direct cellular IAA efflux establishes the more informative process auxin export across the plasma membrane, already represented in this review. Proposed replacements: auxin export across the plasma membrane Supporting Evidence: PMID:35917925 These results show that PIN1 mediates active auxin efflux when expressed in HEK293F cells, and is further activated by D6PK.
GO:0060918 auxin transport	IEA GO_REF:0000117	ACCEPT	Summary: PIN1 is the founding auxin efflux carrier and a central mediator of auxin transport. This ARBA electronic annotation is well supported. Reason: Core biological process; PIN1-mediated efflux is rate-limiting for cellular auxin transport. Supporting Evidence: PMID:9856939 Mutations affecting the PIN-FORMED (PIN1) gene diminish polar auxin transport in Arabidopsis thaliana inflorescence axes. file:ARATH/PIN1/PIN1-deep-research-falcon.md demonstrates PIN1-mediated auxin (IAA) efflux and inhibitor (NPA) binding, matching the UniProt record provided.
GO:0005515 protein binding	IPI PMID:17237354 Interactions among PIN-FORMED and P-glycoprotein auxin trans...	REMOVE	Summary: IntAct interaction with ABCB19/PGP19 (Q9LJX0), a P-glycoprotein auxin transporter that co-acts with PIN1 in directional auxin transport. The bare protein binding term is uninformative about molecular function. Reason: The interaction with ABCB19 is real and biologically relevant to auxin transport, but GO:0005515 is too generic to convey function; per curation guidance bare protein binding is not retained as a core molecular function. Removal does not mean the interaction is false; GO:0005515 protein binding conveys no molecular function for PIN1, and the relationship is captured by the partner's activity annotations and the auxin polar transport module. Supporting Evidence: PMID:17237354 Specific PGP–PIN interactions were seen in yeast two-hybrid and coimmunoprecipitation assays.
GO:0005515 protein binding	IPI PMID:17889649 Antagonistic regulation of PIN phosphorylation by PP2A and P...	REMOVE	Summary: IntAct interaction of PIN1 with PINOID (PID, O64682), the AGC kinase that phosphorylates the PIN1 hydrophilic loop to control apical-basal polarity. The cached abstract reports colocalization and antagonistic PP2A/PID control of PIN loop phosphorylation; the binding assay itself is presumably in the full text. Reason: Removal does not mean the interaction is false. GO:0005515 protein binding conveys no molecular function for PIN1, which is the substrate in this relationship; the kinase-substrate relationship belongs on PID (protein serine/threonine kinase activity with PIN as input). Supporting Evidence: PMID:17889649 PP2A and PINOID both partially colocalize with PINs and act antagonistically on the phosphorylation state of their central hydrophilic loop
GO:0005515 protein binding	IPI PMID:20080776 PIN phosphorylation is sufficient to mediate PIN polarity an...	REMOVE	Summary: IntAct interaction of PIN1 with PID (O64682) in the context of the conserved phosphorylation site that controls PIN polarity. Reason: Removal does not mean the interaction is false. Bare protein binding is uninformative for PIN1 (the kinase substrate); the functional relationship is captured by PID kinase activity and PIN1 polarity annotations. Supporting Evidence: PMID:20080776 The PIN polarity and the resulting auxin flow directionality are mediated by the antagonistic actions of PINOID kinase and protein phosphatase 2A.
GO:0005886 plasma membrane	EXP PMID:20439545 Differential auxin-transporting activities of PIN-FORMED pro...	ACCEPT	Summary: Experimental localization of PIN1 to the plasma membrane in root hair cells, consistent with its function as a PM auxin efflux carrier. Reason: Direct experimental support for the core plasma-membrane localization. Supporting Evidence: PMID:20439545 those PINs were localized in the plasma membrane, where they likely export auxin to the apoplast
GO:0042802 identical protein binding	IDA PMID:35917925 Structural insights into auxin recognition and efflux by Ara...	MODIFY	Summary: Cryo-EM shows PIN1 forms a homodimer with a TM1/TM2/TM7 dimer interface. Identical protein binding (self-association) is directly demonstrated. Reason: The specific supported self-association is homodimerization. PIN1 has a directly resolved TM1/TM2/TM7 dimer interface; the PIN2 assertion is explicitly a homolog-based inference from PIN1, not a PIN2 structure. Identical-protein binding is refined rather than rejected as redundant. Proposed replacements: protein homodimerization activity Supporting Evidence: PMID:35917925 we determined a dimeric structure of PIN1
GO:0042803 protein homodimerization activity	IDA PMID:35917925 Structural insights into auxin recognition and efflux by Ara...	ACCEPT	Summary: PIN1 assembles as a homodimer in the cryo-EM structure, with TM1, TM2 and TM7 forming the dimer interface. Reason: Structurally established homodimerization; an informative molecular function (more specific than identical protein binding). Supporting Evidence: PMID:35917925 TM1, TM2 and TM7 constitute the dimer interface, which consists mainly of hydrophobic residues
GO:0010315 auxin export across the plasma membrane	IDA PMID:35917925 Structural insights into auxin recognition and efflux by Ara...	ACCEPT	Summary: PIN1 expressed in HEK293F cells mediates active IAA efflux across the plasma membrane (enhanced by D6PK, inhibited by NPA). This is the most precise biological-process term for the PIN1 efflux event. Reason: Directly demonstrated auxin export across the PM; a core process. Supporting Evidence: PMID:35917925 These results show that PIN1 mediates active auxin efflux when expressed in HEK293F cells, and is further activated by D6PK. This PIN1-mediated auxin efflux is inhibited by NPA file:ARATH/PIN1/PIN1-deep-research-falcon.md that exports auxin from the cytosol toward the apoplast, thereby enabling
GO:0010329 auxin efflux transmembrane transporter activity	IDA PMID:35917925 Structural insights into auxin recognition and efflux by Ara...	ACCEPT	Summary: Heterologous reconstitution plus cryo-EM with bound IAA establish PIN1 as a direct auxin efflux transmembrane transporter; IAA is coordinated in an intracellular pocket by conserved residues (V51, N112, N478, I582) and mutation of these residues impairs efflux activity. This is the core molecular function. Reason: Strongest, most informative MF annotation; directly supported by structure-function evidence. Supporting Evidence: PMID:35917925 In the structure, IAA is coordinated through both hydrogen bonding and hydrophobic interactions PMID:35917925 All interacting residues (V51, N112, N478 and I582) are highly conserved in PINs file:ARATH/PIN1/PIN1-deep-research-falcon.md Arabidopsis PIN1 was solved in multiple inward-facing conformations (apo, IAA-bound, NPA-bound), revealing a conserved transporter fold and a defined intracellular binding pocket that coordinates IAA. file:ARATH/PIN1/PIN1-deep-research-falcon.md this provides a molecular definition of PIN1’s substrate recognition.
GO:0005515 protein binding	IPI PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l...	REMOVE	Summary: IntAct/UniProt interaction with NPY5/MEL1 (Q0WL52), a MAB4/MEL adaptor recruited to the plasma membrane by PIN1 to maintain polarity. Generic protein binding term is uninformative. Reason: The PIN1-NPY5/MEL1 interaction is mechanistically important for polarity maintenance, but GO:0005515 conveys no specific function. Removal does not mean the interaction is false; GO:0005515 protein binding conveys no molecular function for PIN1, and the relationship is captured by the partner's activity annotations and the auxin polar transport module. Supporting Evidence: PMID:33705718 MAB4/MELs are recruited to the plasma membrane by the PINs and in concert with the AGC kinases maintain PIN polarity
GO:0071944 cell periphery	IDA PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l...	MODIFY	Summary: PIN1 localizes to the cell periphery (plasma membrane and polar PM domains). Correct but a broad parent of the specific plasma-membrane term. Reason: Plasma-membrane imaging supports a more specific location than cell periphery; retain the actual membrane pool rather than treating a general location as a peripheral function. Proposed replacements: plasma membrane Supporting Evidence: PMID:33705718 the polar subcellular plasma membrane (PM) localization of the PIN-FORMED (PIN) auxin efflux carriers
GO:0005886 plasma membrane	IDA PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l...	ACCEPT	Summary: Direct experimental confirmation of PIN1 plasma-membrane localization within the PIN-MAB4/MEL-AGC kinase complex. Reason: Core localization with direct experimental support. Supporting Evidence: PMID:33705718 we demonstrate that PINs, MAB4/MELs, and AGC kinases interact in the same complex at the plasma membrane
GO:0016324 apical plasma membrane	IDA PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l...	ACCEPT	Summary: PIN1 can occupy apical plasma-membrane domains in context-dependent polarity states. Reason: Apical plasma-membrane localization is supported in particular PIN1 expression/phosphorylation contexts, not as a universal shootward orientation. PMID:33705718 also uses predominantly basal PIN1-GFP2 expressed from the PIN2 promoter; that construct must not be quoted as direct evidence of apical PIN1. PID-induced basal-to-apical relocation provides independent support. Supporting Evidence: PMID:15514156 Overexpression of the PINOID protein kinase induces a basal-to-apical shift in PIN localization
GO:0045177 apical part of cell	IDA PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l...	MODIFY	Summary: Reflects PIN1 apical polar localization. Correct but a broad cellular anatomical parent of apical plasma membrane. Reason: The polarized signal is at the apical plasma membrane in the assayed tissue or expression context; refine the broad cellular region without making that polarity universal. Proposed replacements: apical plasma membrane Supporting Evidence: PMID:20407025 Conversely, phosphomimic PIN1:GFP (Ser to Glu) showed apical localization in the shoot apex but did not rescue pin1 inflorescence defects.
GO:0005515 protein binding	IPI PMID:36226797 SUE4, a novel PIN1-interacting membrane protein, regulates a...	REMOVE	Summary: TAIR interaction with SUE4 (AT3G55880), a PIN1-interacting membrane protein that regulates acropetal auxin transport under sulfur deficiency. Generic protein binding term is uninformative. Reason: Biologically relevant interaction but GO:0005515 conveys no specific molecular function. Removal does not mean the interaction is false; GO:0005515 protein binding conveys no molecular function for PIN1, and the relationship is captured by the partner's activity annotations and the auxin polar transport module. Supporting Evidence: PMID:36226797 SUE4, a novel plasma membrane-localized protein, interacts with the polar auxin transporter PIN1
GO:0010168 ER body	IDA PMID:36398993 Mapping of the Classical Mutation rosette Highlights a Role ...	REMOVE	Summary: The cited ER-body experiment assays BIG, whereas PIN1 is assayed separately. Reason: The live GO definition describes a specialized ER-derived body, not general intracellular localization. Full PMID:36398993 distinguishes tomato PIN1 immunostaining (Fig.6G–K), native Arabidopsis pin-mutant rooting assays (Fig.6L–M), and ER-body colocalization of a BIG C-terminal fragment (Fig.7A–C). The latter assay is not PIN1. The specific ER-body assertion is misassigned; this does not claim that PIN1 can never enter the ER during biosynthesis. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6833154.md Confocal images of the C-terminal region of the BIG protein fused to the mScarlet-i (A), the ER marker YFP–HDEL (B) and the overlay of both (C) in epidermal cells of Arabidopsis cotyledons. Arrowheads point to ER bodies.
GO:0048830 adventitious root development	IMP PMID:36398993 Mapping of the Classical Mutation rosette Highlights a Role ...	KEEP AS NON CORE	Summary: Native Arabidopsis higher-order genetics supports PIN1 participation in adventitious rooting. Reason: Full PMID:36398993 directly includes Arabidopsis pin1;2 and higher-order mutants in wound-induced hypocotyl rooting. The 32% decrease in pin1;2 and lack of roots in the quintuple establish a redundant PIN-mediated transport contribution; they do not isolate the quantitative contribution of PIN1 alone. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6833154.md PM-PINs were required for root initiation, with pin1;2 mutants exhibiting a 32% reduction in rooting rates and the quintuple mutant pin1;2;3;4;7 not forming roots at all
GO:0060918 auxin transport	IMP PMID:36398993 Mapping of the Classical Mutation rosette Highlights a Role ...	ACCEPT	Summary: Genetic and physiological evidence that PIN1 contributes to auxin transport (reduced transport rates and NPA hypersensitivity in the relevant mutants). Consistent with PIN1 core role in auxin transport. Reason: Core biological process, corroborated by the founding and structural studies. Supporting Evidence: PMID:36398993 ro mutants were severely inhibited in formation of wound-induced roots (WiRs) and had reduced auxin transport rates.
GO:0010262 somatic embryogenesis	IMP PMID:36345646 Endogenous auxin maintains embryonic cell identity and promo...	KEEP AS NON CORE	Summary: Endogenous auxin (transported by PINs including PIN1) maintains embryonic cell identity and promotes somatic embryo development. This is a downstream developmental process patterned by PIN1-generated auxin gradients. Reason: Pleiotropic developmental output acting via auxin transport; non-core. Supporting Evidence: PMID:36345646 polar auxin transport, with AUXIN/LIKE-AUX influx and PIN-FORMED1 efflux carriers as important drivers, is required for the transition of embryonic cells to proembryos
GO:0005737 cytoplasm	HDA PMID:15610358 High-throughput protein localization in Arabidopsis using Ag...	KEEP AS NON CORE	Summary: PIN1 has an intracellular trafficking pool in addition to its plasma-membrane transport pool. Reason: Cytoplasm includes intracellular membrane compartments and is not synonymous with soluble cytosol. The target-specific HDA supplement was not recovered, but independent PIN1 cycling and BFA-sensitive intracellular accumulation in PMID:18774968 corroborate an intracellular trafficking pool. Retain this secondary location without portraying PIN1 as a soluble cytoplasmic protein. Supporting Evidence: PMID:15610358 These patterns have been classified into five main categories, including cytoplasmic, nuclear, nucleolar, organellar and endomembrane compartments.
GO:0009506 plasmodesma	HDA PMID:21533090 Arabidopsis plasmodesmal proteome.	KEEP AS NON CORE	Summary: PIN1 was detected in the plasmodesmata-enriched proteomic preparation. Reason: The original raw MS Table S1 (s003.xls), not the imported GO table S3, identifies AT1G73590.1 at Excel row1345 with two unique peptides and 4.34% coverage. This supports the curator’s secondary plasmodesmata-associated location, with enrichment/contamination limits and no claim of exclusive residence or a demonstrated plasmodesmal transport mechanism. Supporting Evidence: PMID:21533090 Arabidopsis plasmodesmal proteome. file:ARATH/ABCB1/ABCB1-source-analysis/README.md includes PIN1 AT1G73590.1 at row1345 with 2 unique peptides and 4.34% coverage
GO:0005515 protein binding	IPI PMID:22715043 A PP6-type phosphatase holoenzyme directly regulates PIN pho...	REMOVE	Summary: UniProt interactions with FYPP1 and FYPP3, subunits of a PP6-type phosphatase holoenzyme that dephosphorylates PIN1 and regulates auxin efflux. Generic protein binding term is uninformative. Reason: A real regulatory phosphatase interaction, but GO:0005515 conveys no specific molecular function. Removal does not mean the interaction is false; GO:0005515 protein binding conveys no molecular function for PIN1, and the relationship is captured by the partner's activity annotations and the auxin polar transport module. Supporting Evidence: PMID:22715043 FyPP1 and FyPP3 interact with a subset of PIN proteins and regulate PIN protein phosphorylation and targeting in vivo
GO:0010329 auxin efflux transmembrane transporter activity	IMP PMID:9856939 Regulation of polar auxin transport by AtPIN1 in Arabidopsis...	ACCEPT	Summary: The founding study identified AtPIN1 as a transmembrane component of the auxin efflux carrier; pin1 mutants have diminished polar auxin transport. This mutant-phenotype evidence supports the core efflux transporter function. Reason: Core molecular function, independently established here and later directly demonstrated structurally (PMID:35917925). Supporting Evidence: PMID:9856939 AtPIN1 may act as a transmembrane component of the auxin efflux carrier.
GO:0005515 protein binding	IPI PMID:17586653 Ubiquitin lysine 63 chain forming ligases regulate apical do...	REMOVE	Summary: UniProt interaction (Q9LY87) in the context of K63 ubiquitin chain ligases regulating apical dominance. Generic protein binding term is uninformative about molecular function. Reason: Interaction is recorded but GO:0005515 conveys no specific function. Removal does not mean the interaction is false; GO:0005515 protein binding conveys no molecular function for PIN1, and the relationship is captured by the partner's activity annotations and the auxin polar transport module. Supporting Evidence: PMID:17586653 RGLG2 and PIN1 can interact in the yeast two-hybrid system
GO:0009793 embryo development ending in seed dormancy	IMP PMID:20407025 Phosphorylation of conserved PIN motifs directs Arabidopsis ...	KEEP AS NON CORE	Summary: Loss-of-phosphorylation PIN1 internalizes during embryogenesis causing strong embryo defects, demonstrating a PIN1 requirement in embryo development through proper polar auxin transport. Reason: Important downstream developmental role mediated by PIN1 polar auxin transport; pleiotropic, non-core. Supporting Evidence: PMID:20407025 induced internalization of PIN1:GFP during embryogenesis, leading to strong embryo defects
GO:0005886 plasma membrane	IDA PMID:18337510 Auxin transport inhibitors impair vesicle motility and actin...	ACCEPT	Summary: TAIR IDA annotation of PIN1 plasma-membrane localization from PMID:18337510, a study of how auxin transport inhibitors affect actin-dependent vesicle trafficking. The cached record is abstract-only, so the supporting localization data cannot be inspected here. Reason: Plasma-membrane localization is unambiguously correct for PIN1 (accepted here on other experimental rows, e.g. PMID:33705718 and PMID:35917925). The cached record for PMID:18337510 is abstract-only; the curator read the full text, so an experimental IDA for a clearly correct localization is deferred to the curator rather than overruled from the abstract.
GO:0005886 plasma membrane	IDA PMID:19825598 Plasma membrane-associated SCAR complex subunits promote cor...	ACCEPT	Summary: TAIR IDA annotation of PIN1 plasma-membrane localization from PMID:19825598, whose abstract concerns plasma-membrane localization of the SCAR complex subunits BRK1 and SCAR1 and cortical F-actin. The cached record is abstract-only, so the PIN1 data the curator used cannot be inspected here. Reason: Plasma-membrane localization is unambiguously correct for PIN1 (accepted here on other experimental rows, e.g. PMID:33705718 and PMID:35917925). The cached record for PMID:19825598 is abstract-only; an abstract foregrounding SCAR-complex subunits does not establish that the full text did not also image PIN1, and the curator read the full text, so an experimental IDA for a clearly correct localization is deferred to the curator rather than overruled from the abstract.
GO:0005886 plasma membrane	IDA PMID:18539115 Differential expression of WOX genes mediates apical-basal a...	ACCEPT	Summary: TAIR IDA annotation of PIN1 plasma-membrane localization from PMID:18539115, a study of WOX gene expression in apical-basal axis formation whose abstract mentions PIN1 only as a reporter for auxin response. The cached record is abstract-only, so the supporting localization data cannot be inspected here. Reason: Plasma-membrane localization is unambiguously correct for PIN1 (accepted here on other experimental rows, e.g. PMID:33705718 and PMID:35917925). The cached record for PMID:18539115 is abstract-only; the curator read the full text, so an experimental IDA for a clearly correct localization is deferred to the curator rather than overruled from the abstract.
GO:0009505 plant-type cell wall	IDA PMID:18539115 Differential expression of WOX genes mediates apical-basal a...	UNDECIDED	Summary: The plant-cell-wall assignment cannot be resolved from the accessible reporter description. Reason: The live term denotes material outside the plasma membrane. The accessible PMID:18539115 abstract establishes regulation of a PIN1 reporter but does not resolve reporter signal in the wall versus adjacent plasma membrane; publisher PDF recovery returned 403. A principal plasma-membrane location does not by itself refute the curator’s specific cell-wall assignment. The original target image or topology evidence remains necessary. Supporting Evidence: PMID:35917925 The transmembrane domain of PIN1 has ten transmembrane segments (TM1 to TM10), with both N and C termini located extracellularly
GO:0048825 cotyledon development	IGI PMID:15371311 PIN-FORMED1 and PINOID regulate boundary formation and cotyl...	KEEP AS NON CORE	Summary: PIN1 acts with PINOID to regulate boundary formation and cotyledon development during embryogenesis, via patterning of auxin distribution. Reason: Downstream developmental output of PIN1 auxin transport; pleiotropic, non-core. Supporting Evidence: PMID:15371311 Single mutations in the PIN-FORMED1 (PIN1) and PINOID (PID) genes, which mediate auxin-dependent organ formation, moderately disrupt the symmetric patterning of cotyledons
GO:0009908 flower development	IMP PMID:20407025 Phosphorylation of conserved PIN motifs directs Arabidopsis ...	KEEP AS NON CORE	Summary: PIN1-dependent polar auxin transport is required for flower formation at the shoot apex; defective PIN1 phosphorylation causes inflorescence and flower defects. pin1 mutants form pin-shaped naked inflorescences lacking flowers. Reason: Downstream developmental process patterned by PIN1 auxin transport; pleiotropic, non-core. Supporting Evidence: PMID:20407025 Loss-of-phosphorylation PIN1:green fluorescent protein (GFP) (Ser to Ala) induced inflorescence defects
GO:0010229 inflorescence development	IMP PMID:20407025 Phosphorylation of conserved PIN motifs directs Arabidopsis ...	KEEP AS NON CORE	Summary: PIN1 is required for normal inflorescence development; the defining pin1 phenotype is a naked, pin-shaped inflorescence resulting from failed organ initiation at the shoot apex. Reason: Downstream developmental output of PIN1 polar auxin transport; non-core. Supporting Evidence: PMID:20407025 Loss-of-phosphorylation PIN1:green fluorescent protein (GFP) (Ser to Ala) induced inflorescence defects file:ARATH/PIN1/PIN1-deep-research-falcon.md pin1 mutants exhibit severe organ initiation failures, producing “pin-like” stems with reduced or absent flowers/organs, supporting a causal link between PIN1-mediated PAT and organogenesis.
GO:0048826 cotyledon morphogenesis	IMP PMID:20407025 Phosphorylation of conserved PIN motifs directs Arabidopsis ...	KEEP AS NON CORE	Summary: PIN1-mediated auxin transport during embryogenesis shapes cotyledon formation; phosphorylation-deficient PIN1 produces embryo and cotyledon defects. Reason: Downstream developmental output of PIN1 auxin transport; non-core. Supporting Evidence: PMID:20407025 induced internalization of PIN1:GFP during embryogenesis, leading to strong embryo defects
GO:0010358 leaf shaping	IMP PMID:16971475 ASYMMETRIC LEAVES1 and auxin activities converge to repress ...	KEEP AS NON CORE	Summary: Hay et al. showed that regulated auxin gradients control leaf shape independently of KNOX; the cached abstract does not name PIN1 but the full text (not cached) is where the pin1 mutant analysis would be. PIN1-generated convergence points are well known to pattern leaf serrations. Reason: Abstract-only cache; per curation policy the experimental IMP is deferred to the curator. Leaf shaping is a developmental output of PIN1-mediated transport; non-core. Supporting Evidence: PMID:16971475 We also demonstrate that regulated auxin gradients control leaf shape in a KNOX-independent fashion
GO:0010051 xylem and phloem pattern formation	IMP PMID:16943276 The HVE/CAND1 gene is required for the early patterning of l...	KEEP AS NON CORE	Summary: Alonso-Peral et al. used double-mutant analysis including pin1 to place HVE/CAND1 in a venation pathway independent of PIN1; the IMP for PIN1 in xylem/phloem patterning presumably comes from the pin1 single-mutant venation phenotype reported in the full text. PIN1-dependent auxin canalization in vascular patterning is well established. Reason: Abstract-only cache; the abstract itself shows pin1 was among the mutants analysed. Vascular patterning is a developmental output of PIN1 transport; retained as non-core, deferring to the curator. Supporting Evidence: PMID:16943276 Our analyses of double mutant and transgenic plants indicated that auxin transport and perception act independently to pattern leaf veins
GO:0009630 gravitropism	IMP PMID:16601150 PIN proteins perform a rate-limiting function in cellular au...	KEEP AS NON CORE	Summary: Gravitropism IMP for PIN1 citing Petrasek et al. 2006. The cached abstract covers PIN-mediated rate-limiting auxin efflux in heterologous systems and cultured cells only; any gravitropism data would be in the full text, which is not cached. Reason: Full text not accessible (no PMC/Europe PMC copy; abstract-only cache), so the gravitropism data the curator used were not seen. Gravitropism is plausible for PIN1 because polar auxin transport is required for gravitropic responses; per policy the experimental IMP is deferred to the curator and kept as a non-core downstream physiological output of PIN1 transport. Supporting Evidence: PMID:16601150 the action of PINs in auxin efflux is distinct from PGP, rate-limiting, specific to auxins, and sensitive to auxin transport inhibitors
GO:0009640 photomorphogenesis	TAS PMID:16141452 Brassinosteroids stimulate plant tropisms through modulation...	KEEP AS NON CORE	Summary: Traceable author statement: the paper states that PIN1 is required for basipetal auxin movement and is crucial for shoot vascular development, gravitropic responses and photomorphogenesis. Reason: Supported as a TAS by the cited text; photomorphogenesis is a downstream developmental output of PIN1-mediated transport, so it is non-core. Supporting Evidence: PMID:16141452 the PIN-FORMED1 (PIN1) protein is required for basipetal auxin movement and crucial for shoot vascular development, gravitropic responses, and photomorphogenesis
GO:0009925 basal plasma membrane	IDA PMID:11959844 The Arabidopsis PILZ group genes encode tubulin-folding cofa...	ACCEPT	Summary: PIN1 occupies the basal plasma membrane in vascular transport cells. Reason: Basal vascular plasma-membrane localization is integral to PIN1-mediated directional auxin export. It is a cell/tissue-specific polarity assignment; epidermal convergence patterns in the shoot apex and experimentally induced repolarization are different contexts. Supporting Evidence: PMID:9856939 the AtPIN1 protein was detected at the basal end of auxin transport-competent cells in vascular tissue file:ARATH/PIN1/PIN1-deep-research-falcon.md In vascular tissues and the root stele, PIN1 is frequently described as
GO:0009926 auxin polar transport	IMP PMID:16601150 PIN proteins perform a rate-limiting function in cellular au...	ACCEPT	Summary: PIN proteins, including PIN1, perform the rate-limiting step of cellular auxin efflux that underlies directional polar auxin transport. This is a core biological process for PIN1. Reason: Core biological process; PIN1 polarity dictates the direction of polar auxin transport. Supporting Evidence: PMID:16601150 PINs mediate auxin efflux from mammalian and yeast cells without needing additional plant-specific factors PMID:9856939 Mutations affecting the PIN-FORMED (PIN1) gene diminish polar auxin transport in Arabidopsis thaliana inflorescence axes. file:ARATH/PIN1/PIN1-deep-research-falcon.md which determines the direction of auxin flow between neighboring cells.
GO:0045177 apical part of cell	IDA PMID:16107478 The gene ENHANCER OF PINOID controls cotyledon development i...	MODIFY	Summary: PIN1 apical polar localization observed during cotyledon and embryo development. Correct but a broad anatomical parent of apical plasma membrane. Reason: The polarized signal is at the apical plasma membrane in the assayed tissue or expression context; refine the broad cellular region without making that polarity universal. Proposed replacements: apical plasma membrane Supporting Evidence: PMID:16107478 reversal of polarity of the PIN1 auxin transport facilitator in the apex is only occasional
GO:0048364 root development	IMP PMID:9856939 Regulation of polar auxin transport by AtPIN1 in Arabidopsis...	KEEP AS NON CORE	Summary: PIN1-mediated polar auxin transport is required for normal root system development; pin1 mutants show broad organ-formation defects. Reason: Downstream developmental output of PIN1 auxin transport; non-core. Supporting Evidence: PMID:9856939 abnormalities in the number, size, shape, and position of lateral organs
GO:0048367 shoot system development	IMP PMID:11060241 PIN-FORMED 1 regulates cell fate at the periphery of the sho...	KEEP AS NON CORE	Summary: PIN1 regulates cell fate at the periphery of the shoot apical meristem, controlling organ initiation and overall shoot system development. Reason: Downstream developmental output of PIN1 polar auxin transport; non-core. Supporting Evidence: PMID:11060241 Loss of function severely affects organ initiation, and pin1 mutants are characterised by an inflorescence meristem that does not initiate any flowers

Gene Description

Existing Annotations Review

Core Functions

By localizing asymmetrically (apical or basal) within the plasma membrane, PIN1 sets the direction of intercellular (polar) auxin transport, performing the rate-limiting cellular efflux step that establishes the auxin gradients and maxima patterning plant development.

PIN1 self-associates through a TM1/TM2/TM7 homodimer interface resolved by cryo-EM. Monomeric particles were also observed, so the structure does not establish that every active native PIN1 molecule is dimeric.

References

Deep Research

Falcon

📚 Additional Documentation

Notes

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