Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Automatic assignment of GO terms using logical inference, based on on inter-ontology links
Localization of the auxin permease AUX1 suggests two functionally distinct hormone transport pathways operate in the Arabidopsis root apex.
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AUX1 is a multi-pass integral plasma membrane protein, established by experimental localization in root cells. This UniProt subcellular-location mapping is consistent with the curated Cell membrane location.
"AUX1, asymmetrically localized to the plasma membrane of root protophloem cells, is proposed to promote the acropetal, post-phloem movement of auxin to the root apex."
Nematode-induced changes of transporter gene expression in Arabidopsis roots.
High-affinity auxin transport by the AUX1 influx carrier protein.
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This biological-process term is inferred from the molecular function GO:0010328 (auxin influx transmembrane transporter activity) and exactly captures the core role of AUX1 - importing auxin (IAA) into cells. It is strongly supported by direct experimental transport data.
"Upon expression of AUX1 in Xenopus oocytes, saturable, pH-dependent uptake of 3H-IAA was measured."
AXR4 is required for localization of the auxin influx facilitator AUX1.
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This generic protein binding annotation derives from a large-scale phytohormone interactome screen; the WITH/FROM partner is UniProtKB:Q9FZ33 (AXR4), the ER accessory protein required for AUX1 trafficking to the plasma membrane. The term protein binding is uninformative about molecular function.
"AXR4 is a previously unidentified accessory protein of the endoplasmic reticulum (ER) that regulates localization of AUX1 but not of PIN proteins."
Auxin transport: a field in flux.
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AUX1 is one of the carrier proteins that mediate carrier-based polar auxin transport, contributing the influx (uptake) component alongside PIN efflux carriers. The review (TAS) places AUX1 within the polar auxin transport system that establishes directional auxin fluxes in the root apex.
"Auxin moves between plant cells through a combination of membrane diffusion and carrier-mediated transport. Several classes of membrane proteins that facilitate auxin uptake and efflux have recently been identified in Arabidopsis."
Vectorial information for Arabidopsis planar polarity is mediated by combined AUX1, EIN2, and GNOM activity.
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In aux1 ein2 gnom mutants, root hair positioning switches from polar to axial and the auxin gradient is lost, indicating AUX1 acts with EIN2 and GNOM in patterning root hair cells. The annotation captures the role of AUX1 in root hair development via auxin gradient formation.
"In aux1;ein2;gnom eb triple mutant roots, hairs display axial (apical or basal) instead of coordinate polar (basal) position"
Subcellular trafficking of the Arabidopsis auxin influx carrier AUX1 uses a novel pathway distinct from PIN1.
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Live-cell imaging shows AUX1 resides at the apical plasma membrane and at highly dynamic subpopulations of Golgi apparatus and endosomes in all cell types, with PM and intracellular pools interconnected by actin-dependent constitutive trafficking. The endosomal pool reflects AUX1 trafficking rather than its functional transport site.
"AUX1 resides at the apical plasma membrane of protophloem cells and at highly dynamic subpopulations of Golgi apparatus and endosomes in all cell types."
Auxin-dependent regulation of lateral root positioning in the basal meristem of Arabidopsis.
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Lateral roots are spaced along the primary root in a regular pattern that correlates with gravity-induced waving and depends on AUX1; AUX1 contributes to auxin-dependent priming of pericycle cells for lateral root initiation. Mutant-phenotype evidence links AUX1 to lateral root positioning/formation.
"lateral roots are spaced along the main axis in a regular left-right alternating pattern that correlates with gravity-induced waving and depends on AUX1, an auxin influx carrier essential for gravitropic response."
The binding of auxin to the Arabidopsis auxin influx transporter AUX1.
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AUX1 expressed in baculovirus-infected insect cell membranes binds IAA directly with a Kd of about 2.6 microM, comparable to its transport Km. Auxin analogues and influx inhibitors specifically displace IAA, confirming direct, specific binding of the auxin substrate.
"These membranes proved suitable for determination of the binding of IAA to AUX1 and enabled us to determine a K(d) of 2.6 mum, comparable with estimates for the K(m) for IAA transport."
The auxin influx carrier LAX3 promotes lateral root emergence.
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AUX1 functions with its paralog LAX3 in auxin influx that promotes lateral root development; LAX3 acts in cortical/epidermal cells overlaying primordia to promote emergence, while AUX1 contributes to lateral root formation through auxin distribution. Genetic interaction within the AUX1/LAX family.
"Auxin induces the expression of a previously uncharacterized auxin influx carrier LAX3 in cortical and epidermal cells directly overlaying new primordia."
The AUX1 LAX family of auxin influx carriers is required for the establishment of embryonic root cell organization in Arabidopsis thaliana.
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aux1 lax mutants have enlarged radicle root caps with altered columella cell number, size and organization, indicating that AUX1/LAX auxin influx carriers act redundantly in establishing embryonic root cap cell pattern. AUX1 contributes within this auxin-transport-dependent developmental process.
"aux1 lax mutants have a larger radicle root cap than the wild type and this is associated with a significant increase in the root-cap cell number, average cell size, or both."
Extensive signal integration by the phytohormone protein network.
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This generic protein binding annotation derives from a large-scale phytohormone interactome screen; the WITH/FROM partner is UniProtKB:Q9FZ33 (AXR4), the ER accessory protein required for AUX1 trafficking to the plasma membrane. The term protein binding is uninformative about molecular function.
"we experimentally generated a systems-level map of the Arabidopsis phytohormone signalling network, consisting of more than 2,000 binary protein-protein interactions."
Endogenous auxin maintains embryonic cell identity and promotes somatic embryo development in Arabidopsis.
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AUX1 (as part of the AUX1/LAX influx carrier system together with PIN efflux carriers) contributes to polar auxin transport required for somatic embryo development. This is an auxin-transport-dependent developmental process, peripheral to the core transport function of AUX1 and involving redundancy with LAX/PIN family members.
"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 and, later, for correct cell fate specification and differentiation."
Arabidopsis AUX1 gene: a permease-like regulator of root gravitropism.
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aux1 mutations abolish root gravitropic curvature and confer auxin-resistant root growth; AUX1 is expressed in root apical tissues that regulate gravitropic curvature. AUX1-facilitated auxin uptake into distal elongation zone tissues is required for the differential growth underlying root gravitropism.
"Mutations within the AUX1 gene confer an auxin-resistant root growth phenotype and abolish root gravitropic curvature."
The Arabidopsis AUX1 gene: a model system to study mRNA processing in plants.
Falcon (Edison Scientific) deep research report for AUX1
Structural basis of auxin binding and transport by Arabidopsis thaliana AUX1.
Structural insights into auxin influx mediated by the Arabidopsis AUX1.
Structural basis of auxin recognition and transport by the plant influx carrier AUX1.
The novel cyst nematode effector protein 19C07 interacts with the Arabidopsis auxin influx transporter LAX3 to control feeding site development.