PINOID (PID) is a plant AGCVIII serine/threonine protein kinase that phosphorylates PIN auxin efflux carriers. Its peripheral plasma-membrane association involves its insertion domain and lipid interactions. PID promotes phosphorylation-dependent PIN sorting, including basal-to-apical shifts in particular developmental contexts, and also directly activates PIN-mediated auxin efflux. These functions have different experimental readouts: kinase distribution need not itself be apically enriched, and transport activation is not equivalent to repolarization. PID cooperates with related WAG kinases and MAB4/MEL proteins and is opposed by phosphatases in controlling PIN-dependent auxin distribution, cotyledon and floral development, and root tropic responses.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004672 protein kinase activity | IDA PMID:16601102 Phosphorylation and activation of PINOID by the phospholipid... | MODIFY | Summary: Recombinant PID autophosphorylates and phosphorylates exogenous substrates. Reason: Direct PIN phosphorylation establishes protein serine/threonine kinase activity, a more specific function than this broad kinase term and already retained in this review. Proposed replacements: protein serine/threonine kinase activity Supporting Evidence: PMID:16601102 We demonstrate that intramolecular PID autophosphorylation is required for the ability of PID to phosphorylate an exogenous substrate. |
| GO:0004672 protein kinase activity | IEA GO_REF:0000002 | MODIFY | Summary: Generic protein kinase activity from InterPro. Reason: Direct PIN phosphorylation establishes protein serine/threonine kinase activity, a more specific function than this broad kinase term and already retained in this review. Proposed replacements: protein serine/threonine kinase activity Supporting Evidence: PMID:16601102 We demonstrate that intramolecular PID autophosphorylation is required for the ability of PID to phosphorylate an exogenous substrate. |
| GO:0004674 protein serine/threonine kinase activity | IBA GO_REF:0000033 | ACCEPT | Summary: AGCVIII family serine/threonine kinase activity; PID (AT2G34650) is itself an experimental donor. Reason: Core molecular function, experimentally established for PID. Supporting Evidence: PMID:16601102 We demonstrate that intramolecular PID autophosphorylation is required for the ability of PID to phosphorylate an exogenous substrate. PMID:20040538 The Ser/Thr protein kinase PINOID (PID) catalyzes PIN phosphorylation and crucially contributes to the regulation of apical-basal PIN polarity. |
| GO:0004674 protein serine/threonine kinase activity | IDA PMID:10693763 Regulation of auxin response by the protein kinase PINOID. | ACCEPT | Summary: PID encodes an active serine/threonine protein kinase. Reason: Core MF. Supporting Evidence: PMID:10693763 PID, which encodes a serine-threonine protein kinase |
| GO:0004674 protein serine/threonine kinase activity | IEA GO_REF:0000003 | ACCEPT | Summary: EC 2.7.11.1 mapping. Reason: Correct; core MF. Supporting Evidence: PMID:10693763 PID, which encodes a serine-threonine protein kinase |
| GO:0004674 protein serine/threonine kinase activity | ISS PMID:11641228 The PINOID protein kinase regulates organ development in Ara... | ACCEPT | Summary: Serine/threonine kinase by sequence similarity, consistent with later direct evidence. Reason: Core MF. Supporting Evidence: PMID:11641228 The PINOID gene was recently cloned and found to encode a protein-serine/threonine kinase. |
| GO:0005515 protein binding | IPI PMID:12857841 PINOID-mediated signaling involves calcium-binding proteins. | REMOVE | Summary: Physical interaction of PID with TOUCH3 (CML12), a calmodulin-related protein. GO:0005515 protein binding conveys no molecular function. Reason: The interaction assertion from PMID:12857841 is retained as mechanistic context (UniProtKB:P25071), but bare protein binding does not specify the kinase reaction or a distinct functional binding role. REMOVE follows the uninformative-binding policy and does not deny the reported interaction. Supporting Evidence: PMID:12857841 PID interacts with two calcium-binding proteins: TOUCH3 (TCH3), a calmodulin-related protein, and PID-BINDING PROTEIN 1 (PBP1) |
| GO:0005515 protein binding | IPI PMID:12857841 PINOID-mediated signaling involves calcium-binding proteins. | REMOVE | Summary: Physical interaction of PID with PBP1 (PID-BINDING PROTEIN 1). GO:0005515 protein binding conveys no molecular function. Reason: The interaction assertion from PMID:12857841 is retained as mechanistic context (UniProtKB:Q9LSQ6), but bare protein binding does not specify the kinase reaction or a distinct functional binding role. REMOVE follows the uninformative-binding policy and does not deny the reported interaction. Supporting Evidence: PMID:12857841 PBP1 was found to stimulate the autophosphorylation activity of PID |
| GO:0005515 protein binding | IPI PMID:16601102 Phosphorylation and activation of PINOID by the phospholipid... | REMOVE | Summary: Physical interaction of PID with PDK1, which trans-phosphorylates and activates PID. GO:0005515 protein binding conveys no molecular function. Reason: The interaction assertion from PMID:16601102 is retained as mechanistic context (UniProtKB:Q9XF67), but bare protein binding does not specify the kinase reaction or a distinct functional binding role. REMOVE follows the uninformative-binding policy and does not deny the reported interaction. Supporting Evidence: PMID:16601102 We find that Arabidopsis PDK1 interacts with PID, and that transphosphorylation by PDK1 increases PID autophosphorylation. |
| GO:0005515 protein binding | IPI PMID:17889649 Antagonistic regulation of PIN phosphorylation by PP2A and P... | REMOVE | Summary: Physical interaction of PID with PIN1, its phosphorylation substrate. The substrate relationship is captured by the kinase activity annotation. GO:0005515 protein binding conveys no molecular function. Reason: The interaction assertion from PMID:17889649 is retained as mechanistic context (UniProtKB:Q9C6B8), but bare protein binding does not specify the kinase reaction or a distinct functional binding role. REMOVE follows the uninformative-binding policy and does not deny the reported interaction. 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: Physical interaction of PID with PIN1, its phosphorylation substrate. The substrate relationship is captured by the kinase activity annotation. GO:0005515 protein binding conveys no molecular function. Reason: The interaction assertion from PMID:20080776 is retained as mechanistic context (UniProtKB:Q9C6B8), but bare protein binding does not specify the kinase reaction or a distinct functional binding role. REMOVE follows the uninformative-binding policy and does not deny the reported interaction. 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:0005515 protein binding | IPI PMID:32612234 Extensive signal integration by the phytohormone protein net... | REMOVE | Summary: Physical interaction of PID with MKK7/BUD1 in a large-scale phytohormone interactome (Y2H). GO:0005515 protein binding conveys no molecular function. Reason: The interaction assertion from PMID:32612234 is retained as mechanistic context (UniProtKB:Q9LPQ3), but bare protein binding does not specify the kinase reaction or a distinct functional binding role. REMOVE follows the uninformative-binding policy and does not deny the reported interaction. Supporting Evidence: PMID:32612234 we experimentally generated a systems-level map of the Arabidopsis phytohormone signalling network |
| GO:0005515 protein binding | IPI PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l... | REMOVE | Summary: Physical interaction of PID with MEL1/NPY5, an NPH3-family PIN polarity adaptor. GO:0005515 protein binding conveys no molecular function. Reason: The interaction assertion from PMID:33705718 is retained as mechanistic context (UniProtKB:Q0WL52), but bare protein binding does not specify the kinase reaction or a distinct functional binding role. REMOVE follows the uninformative-binding policy and does not deny the reported interaction. Supporting Evidence: PMID:33705718 GST-MEL1 and HIS-PID |
| GO:0005515 protein binding | IPI PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l... | REMOVE | Summary: Physical interaction of PID with MAB4/NPY1 (ENHANCER OF PINOID). GO:0005515 protein binding conveys no molecular function. Reason: The interaction assertion from PMID:33705718 is retained as mechanistic context (UniProtKB:Q8H1D3), but bare protein binding does not specify the kinase reaction or a distinct functional binding role. REMOVE follows the uninformative-binding policy and does not deny the reported interaction. Supporting Evidence: PMID:33705718 Additional pull-down assays revealed physical interactions between GST-MAB4 and HIS-PID |
| GO:0005515 protein binding | IPI PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l... | REMOVE | Summary: Physical interaction of PID with the PIN2 hydrophilic loop, its phosphorylation substrate. GO:0005515 protein binding conveys no molecular function. Reason: The interaction assertion from PMID:33705718 is retained as mechanistic context (UniProtKB:Q9LU77), but bare protein binding does not specify the kinase reaction or a distinct functional binding role. REMOVE follows the uninformative-binding policy and does not deny the reported interaction. Supporting Evidence: PMID:33705718 GST-PID/WAGs and HIS-PIN2HL |
| GO:0005524 ATP binding | IEA GO_REF:0000002 | ACCEPT | Summary: ATP binding of the kinase domain. Reason: ATP is the phosphate-donor substrate of the experimentally demonstrated kinase reaction. Binding is integral to the catalytic mechanism, not a peripheral activity merely because it is a binding annotation. Supporting Evidence: PMID:16601102 We demonstrate that intramolecular PID autophosphorylation is required for the ability of PID to phosphorylate an exogenous substrate. |
| GO:0005634 nucleus | IBA GO_REF:0000033 | UNDECIDED | Summary: Nuclear localization remains unresolved for PID. Reason: The ancestral PTN000682243 or AtSubP nuclear assignment is not resolved by the recovered target data. PID has strong plasma-membrane evidence, but principal membrane localization does not exclude a nuclear population. The cited AGCVIII comparison is heterologous and highlights WAG1/KIPK nuclear versus PID peripheral enrichment; it does not establish an exhaustive negative for this target. The current family source lacks a recovered authoritative IBD record for this node, so no loss/node-pruning assertion is made. Propagation Review Root cause: UNRESOLVED Sources checked: PANTHER:PTN000682243 UNRESOLVED This ancestral identifier and the WAG1/KIPK-associated seed list are recorded in the original payload. A target-resolved IBD/tree placement was not recovered for the current family; plasma-membrane imaging alone cannot establish nuclear exclusion. No inferred node placement or source failure is asserted. Supporting Evidence: PMID:16973627 preferentially localized to the cytoplasm (AGC1-7), nucleus (WAG1 and KIPK), and the cell periphery (PID) |
| GO:0005634 nucleus | ISM GO_REF:0000122 | UNDECIDED | Summary: Nuclear localization remains unresolved for PID. Reason: The ancestral PTN000682243 or AtSubP nuclear assignment is not resolved by the recovered target data. PID has strong plasma-membrane evidence, but principal membrane localization does not exclude a nuclear population. The cited AGCVIII comparison is heterologous and highlights WAG1/KIPK nuclear versus PID peripheral enrichment; it does not establish an exhaustive negative for this target. The current family source lacks a recovered authoritative IBD record for this node, so no loss/node-pruning assertion is made. Supporting Evidence: PMID:16973627 We present evidence that PID insertion domain sequences are sufficient to direct the observed peripheral localization. |
| GO:0005737 cytoplasm | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: A cytosolic pool of PID exists (e.g. after PM dissociation by PAO or loss of the insertion domain), but the active pool acts at the plasma membrane. Reason: Correct but non-core location. Supporting Evidence: PMID:33705718 PM association of PID, and thus also apical PIN phosphorylation, is sensitive to the PIP-kinase inhibitor phenylarsine oxide (PAO) |
| GO:0005829 cytosol | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: UniProt subcellular location includes cytosol. Reason: A cytosolic pool exists but PID functions at the plasma membrane. Supporting Evidence: PMID:33705718 PM association of PID, and thus also apical PIN phosphorylation, is sensitive to the PIP-kinase inhibitor phenylarsine oxide (PAO) |
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: PID associates with the inner leaflet of the plasma membrane where it phosphorylates PINs; PID is an experimental donor of this IBA. Reason: Core location. Supporting Evidence: PMID:33705718 when PID-CFP was co-expressed with PIN1-GFP and MAB4- or MEL1-RFP in protoplasts, all three proteins colocalized strongly at the PM |
| GO:0005886 plasma membrane | IDA PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l... | ACCEPT | Summary: PID colocalizes with PINs and MAB4/MEL proteins at the plasma membrane. Reason: Core location. Supporting Evidence: PMID:33705718 when PID-CFP was co-expressed with PIN1-GFP and MAB4- or MEL1-RFP in protoplasts, all three proteins colocalized strongly at the PM |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular location: plasma membrane (peripheral). Reason: Core location. Supporting Evidence: PMID:33705718 when PID-CFP was co-expressed with PIN1-GFP and MAB4- or MEL1-RFP in protoplasts, all three proteins colocalized strongly at the PM |
| GO:0009733 response to auxin | IEP PMID:11641228 The PINOID protein kinase regulates organ development in Ara... | KEEP AS NON CORE | Summary: PID transcription is auxin-inducible. Reason: Expression response, consistent with a feedback loop on auxin transport; non-core. Supporting Evidence: PMID:11641228 we show that the PINOID gene is inducible by auxin |
| GO:0009734 auxin-activated signaling pathway | IMP PMID:10693763 Regulation of auxin response by the protein kinase PINOID. | MARK AS OVER ANNOTATED | Summary: The early auxin-insensitive-like overexpression phenotype was interpreted as altered auxin signaling; later target experiments establish PIN-mediated transport regulation as a mechanism for changed auxin distribution. Reason: The cited experiments establish PID-dependent PIN phosphorylation, localization and auxin efflux, rather than participation in an auxin-perception signaling cascade. Interpreting the altered growth response as direct signaling-pathway participation therefore exceeds these experiments, so retain MARK_AS_OVER_ANNOTATED. This judgment does not equate every auxin-activated pathway with TIR1/AFB or exclude a possible context-specific noncanonical signaling role for PID. Supporting Evidence: PMID:10693763 implying that PID, which encodes a serine-threonine protein kinase, negatively regulates auxin signaling PMID:11641228 The results presented here indicate that PINOID functions as a positive regulator of polar auxin transport. PMID:16731587 we demonstrate that the protein kinase PINOID (PID) positively regulates auxin efflux |
| GO:0009926 auxin polar transport | IMP PMID:10693763 Regulation of auxin response by the protein kinase PINOID. | ACCEPT | Summary: pid mutants phenocopy pin1 and auxin-transport-inhibitor-grown plants. Reason: Consistent with PID as a regulator of polar auxin transport. Supporting Evidence: PMID:10693763 mimics that of plants grown on auxin transport inhibitors or of plants mutant for the auxin efflux carrier PINFORMED (PIN) |
| GO:0009926 auxin polar transport | IMP PMID:16731587 PINOID positively regulates auxin efflux in Arabidopsis root... | ACCEPT | Summary: PID overexpression enhances auxin efflux in root hair cells and tobacco cells. Reason: Consistent with PID as a positive regulator of auxin efflux/polar transport. Supporting Evidence: PMID:16731587 we demonstrate that the protein kinase PINOID (PID) positively regulates auxin efflux |
| GO:0009926 auxin polar transport | IMP PMID:19363095 PINOID kinase regulates root gravitropism through modulation... | ACCEPT | Summary: pid-9 seedlings have reduced basipetal (shootward) IAA transport in roots. Reason: PID performs regulatory phosphorylation that changes PIN-dependent auxin transport. This biological contribution is supported by native transport/gravitropism studies and direct kinase/efflux assays; it is not inferred from a relationship qualifier. Supporting Evidence: PMID:19363095 Basipetal indole-3-acetic acid transport and gravitropism are reduced in pid-9 seedlings |
| GO:0009958 positive gravitropism | IMP PMID:19363095 PINOID kinase regulates root gravitropism through modulation... | KEEP AS NON CORE | Summary: pid-9 roots have delayed gravitropism, via modulation of PIN2-dependent shootward auxin transport. Reason: Physiological outcome of the transport-regulatory role; non-core. Supporting Evidence: PMID:19363095 Basipetal indole-3-acetic acid transport and gravitropism are reduced in pid-9 seedlings |
| GO:0009986 cell surface | IDA PMID:16731587 PINOID positively regulates auxin efflux in Arabidopsis root... | MODIFY | Summary: PID localizes to the cell boundary (inner face of the plasma membrane). GO "cell surface" denotes the external face of the cell, which is not where this cytoplasmic kinase resides. Reason: Replace with plasma membrane, the specific location PID occupies at the cell boundary (inner leaflet, via its polybasic insertion domain) and which this review accepts as core from three other rows. Cell periphery is not used as the replacement because PID already carries GO:0071944 by IDA from this same paper, and that term is less informative than plasma membrane. Proposed replacements: plasma membrane Supporting Evidence: PMID:16731587 Localization of PID or PIN3 at the cell boundary was disrupted by brefeldin A and staurosporine. |
| GO:0016301 kinase activity | ISS PMID:13678909 Growth signalling pathways in Arabidopsis and the AGC protei... | MODIFY | Summary: Kinase activity by similarity (AGC kinase review). Reason: Direct PIN phosphorylation establishes protein serine/threonine kinase activity, a more specific function than this broad kinase term and already retained in this review. Proposed replacements: protein serine/threonine kinase activity Supporting Evidence: PMID:13678909 The Arabidopsis AGC kinases contain sequence motives required for the docking of PDK1 and phosphorylation of their activation loop in the kinase catalytic domain. |
| GO:0016324 apical plasma membrane | IDA PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l... | ACCEPT | Summary: PID acts at plasma-membrane domains including the apical domain. Reason: PID can act at the apical plasma membrane, but the 2021 paper explicitly describes PID/WAG distribution as apolar and distinguishes kinase localization from the polarity of its PIN substrate. Retain an apical pool without asserting universal apical enrichment. Supporting Evidence: PMID:33705718 PM association of PID, and thus also apical PIN phosphorylation, is sensitive to the PIP-kinase inhibitor phenylarsine oxide (PAO) |
| GO:0048766 root hair initiation | IMP PMID:16731587 PINOID positively regulates auxin efflux in Arabidopsis root... | MARK AS OVER ANNOTATED | Summary: Ectopic PID suppresses root-hair growth in a transport bioassay. Reason: Full PMID:16731587 expresses PID from the heterologous root-hair-specific ATEXPA7 promoter to use auxin-sensitive hair growth as an efflux assay. Auxin and transport/kinase inhibitors rescue the phenotype. This is real PID catalytic sufficiency in an imposed cellular context, but does not establish that endogenous PID normally executes this specific root-hair developmental program; the evidence supports PIN regulation more directly. Supporting Evidence: PMID:16731587 Overexpression of PID (PIDox) or the auxin efflux carrier component PINFORMED3 (PIN3, PIN3ox), specifically in the root hair cell, greatly suppressed root hair growth. |
| GO:0048767 root hair elongation | IMP PMID:16731587 PINOID positively regulates auxin efflux in Arabidopsis root... | MARK AS OVER ANNOTATED | Summary: Ectopic PID suppresses root-hair growth in a transport bioassay. Reason: Full PMID:16731587 expresses PID from the heterologous root-hair-specific ATEXPA7 promoter to use auxin-sensitive hair growth as an efflux assay. Auxin and transport/kinase inhibitors rescue the phenotype. This is real PID catalytic sufficiency in an imposed cellular context, but does not establish that endogenous PID normally executes this specific root-hair developmental program; the evidence supports PIN regulation more directly. Supporting Evidence: PMID:16731587 Overexpression of PID (PIDox) or the auxin efflux carrier component PINFORMED3 (PIN3, PIN3ox), specifically in the root hair cell, greatly suppressed root hair growth. |
| GO:0048825 cotyledon development | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ARBA rule for cotyledon development, reflecting pid cotyledon defects. Reason: Developmental consequence of PID-regulated PIN polarity; non-core. Supporting Evidence: PMID:15371311 the pin1 pid double mutant displays a striking phenotype that completely lacks cotyledons and bilateral symmetry |
| GO:0048825 cotyledon development | IGI PMID:15371311 PIN-FORMED1 and PINOID regulate boundary formation and cotyl... | KEEP AS NON CORE | Summary: pin1 pid double mutants completely lack cotyledons; PID and PIN1 act redundantly in cotyledon outgrowth by repressing CUC1/2 and STM. Reason: Developmental outcome of PID-dependent PIN polarity; non-core. Supporting Evidence: PMID:15371311 the pin1 pid double mutant displays a striking phenotype that completely lacks cotyledons and bilateral symmetry |
| GO:0048825 cotyledon development | IGI PMID:18000043 NPY1, a BTB-NPH3-like protein, plays a critical role in auxi... | KEEP AS NON CORE | Summary: npy1 pid double mutants fail to form cotyledons. Reason: Developmental outcome; non-core. Supporting Evidence: PMID:18000043 The npy1 pid double mutants fail to form any cotyledons |
| GO:0048825 cotyledon development | IGI PMID:19075219 NPY genes and AGC kinases define two key steps in auxin-medi... | KEEP AS NON CORE | Summary: pid pid2 wag1 wag2 quadruple mutants lack cotyledons. Reason: Developmental outcome; non-core. Supporting Evidence: PMID:19075219 Simultaneous disruption of PID and its 3 closest homologs (PID2, WAG1, and WAG2) completely abolishes the formation of cotyledons |
| GO:0048827 phyllome development | IGI PMID:18000043 NPY1, a BTB-NPH3-like protein, plays a critical role in auxi... | KEEP AS NON CORE | Summary: PID with NPY1 is required for flower/organ primordium formation. Reason: Developmental outcome of auxin transport regulation; non-core. Supporting Evidence: PMID:18000043 We demonstrate that NPY1 works with the protein kinase PID, which is homologous to PHOT1, to regulate auxin-mediated plant development. |
| GO:0071944 cell periphery | IDA PMID:33705718 AGC kinases and MAB4/MEL proteins maintain PIN polarity by l... | MODIFY | Summary: Cell periphery localization of PID. Reason: The imaged cell-peripheral kinase pool is at the plasma membrane, supported independently by target localization and membrane-recruitment studies. Refine the broad cellular region. Proposed replacements: plasma membrane Supporting Evidence: PMID:33705718 when PID-CFP was co-expressed with PIN1-GFP and MAB4- or MEL1-RFP in protoplasts, all three proteins colocalized strongly at the PM |
| GO:0106310 protein serine kinase activity | IEA GO_REF:0000116 | ACCEPT | Summary: Rhea-based protein serine kinase activity. PID phosphorylates serines in the PIN central hydrophilic loop. Reason: Correct and consistent with the substrate (Ser) specificity on PINs. Supporting Evidence: PMID:20040538 The Ser/Thr protein kinase PINOID (PID) catalyzes PIN phosphorylation and crucially contributes to the regulation of apical-basal PIN polarity. |
| GO:2000012 regulation of auxin polar transport | IDA PMID:24948515 Auxin efflux by PIN-FORMED proteins is activated by two diff... | NEW | Summary: NEW annotation. PID (and WAG kinases) directly activate PIN-mediated auxin efflux in Xenopus oocytes, and PID overexpression enhances auxin efflux in plant cells; PID is therefore a direct regulator of polar auxin transport, in addition to setting PIN polarity. Reason: Retain the inherited proposal because PID itself phosphorylates and activates transporters, directly regulating the rate of auxin transport. PMID:24948515 separates this activation activity from the polarity changes characterized in the native trafficking studies. No inference from inert relationship qualifiers is used. Supporting Evidence: PMID:24948515 PIN-mediated auxin transport is directly activated by D6 PROTEIN KINASE (D6PK) and PINOID (PID)/WAG kinases of the Arabidopsis AGCVIII kinase family PMID:16731587 we demonstrate that the protein kinase PINOID (PID) positively regulates auxin efflux |
| GO:1901703 protein localization involved in auxin polar transport | IDA PMID:15514156 A PINOID-dependent binary switch in apical-basal PIN polar t... | NEW | Summary: NEW annotation. PID phosphorylation of PIN hydrophilic loops is the step that sorts PINs to the apical plasma membrane: PID overexpression shifts PINs basal-to-apical and pid loss shifts PIN1 apical-to-basal at the inflorescence apex. PID thus catalyses the regulatory step of PIN polar targeting that determines auxin flow direction. Reason: Retain the inherited proposal for the phosphorylation-dependent control of PIN trafficking/polar targeting. PID performs regulatory work in localization, and native genetic/cell-biological evidence in PMID:15514156 and PMID:20040538 supports the role; this is not a claim that PID itself transports auxin. Supporting Evidence: PMID:15514156 Overexpression of the PINOID protein kinase induces a basal-to-apical shift in PIN localization PMID:15514156 Our results show that a PINOID-dependent binary switch controls PIN polarity and mediates changes in auxin flow to create local gradients for patterning processes. PMID:20040538 The Ser/Thr protein kinase PINOID (PID) catalyzes PIN phosphorylation and crucially contributes to the regulation of apical-basal PIN polarity. |
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Download this section (compressed HTML)Q: How do PID-preferred phosphosites (S1-S3 in the PIN loop) differ mechanistically from D6PK-preferred sites in specifying polarity versus transport activation?
Suggested experts: Plant AGC kinase researchers, Auxin transport biochemists
Experiment: Combine PID overexpression with mel1234 mutants and measure PIN1/PIN2 polarity and FRAP-based lateral diffusion in root epidermis and shoot apex.
Hypothesis: PID-dependent apical PIN targeting requires MAB4/MEL-mediated limitation of lateral diffusion.
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