NCU01540 is a predicted SPX-regulated phosphate transporter of the fungal Pho87/Pho90/Pho91 group. Its SPX regulatory domain and multi-pass permease region support phosphate transport and phosphate/polyphosphate homeostasis. The Pho91 subfamily assignment favors a role in intracellular phosphate handling, but its resident membrane, transport direction, and coupling ion in Neurospora crassa remain unresolved.
Summary: The SPX plus CitMHS permease architecture and Pho91 subfamily assignment support phosphate transport by transfer from experimentally characterized fungal Pho87/Pho90/Pho91 transporters. This supports the curated phosphate-transport IBA without specifying coupling or direction.
Supporting Evidence:
file:NEUCR/NCU01540/NCU01540-uniprot.txt
DR PANTHER; PTHR10283:SF92; LOW-AFFINITY PHOSPHATE TRANSPORTER PHO91; 1.
the low-affinity transporter Pho91 limits poly P accumulation in a strain lacking PHO85. This phenotype was not caused by a regulatory effect on the PHO pathway, but can be attributed to the unexpected localization of Pho91 in the vacuolar membrane.
Summary: The IBA derives from PTN000031793 in a broad transporter family. Pho87/Pho90 operate at the plasma membrane whereas the characterized Pho91 is vacuolar, and the target is classified in a Pho91 subfamily. The available evidence does not resolve whether the ancestral plasma-membrane assertion applies to this filamentous-fungal branch; neither location is treated as experimentally established for NCU01540.
Supporting Evidence:
file:NEUCR/NCU01540/NCU01540-uniprot.txt
DR PANTHER; PTHR10283:SF92; LOW-AFFINITY PHOSPHATE TRANSPORTER PHO91; 1.
the low-affinity transporter Pho91 limits poly P accumulation in a strain lacking PHO85. This phenotype was not caused by a regulatory effect on the PHO pathway, but can be attributed to the unexpected localization of Pho91 in the vacuolar membrane.
Summary: The characterized yeast Pho91 transporter changes vacuolar polyphosphate accumulation through phosphate handling. This supports a conserved indirect contribution to polyphosphate metabolism, not intrinsic polyphosphate synthesis or hydrolysis.
Supporting Evidence:
file:NEUCR/NCU01540/NCU01540-uniprot.txt
DR PANTHER; PTHR10283:SF92; LOW-AFFINITY PHOSPHATE TRANSPORTER PHO91; 1.
the low-affinity transporter Pho91 limits poly P accumulation in a strain lacking PHO85. This phenotype was not caused by a regulatory effect on the PHO pathway, but can be attributed to the unexpected localization of Pho91 in the vacuolar membrane.
Summary: Phosphate movement is the conserved process of the supported Pho91-like transporter family; the target subfamily assignment and yeast transporter experiments ground this inference.
Supporting Evidence:
file:NEUCR/NCU01540/NCU01540-uniprot.txt
DR PANTHER; PTHR10283:SF92; LOW-AFFINITY PHOSPHATE TRANSPORTER PHO91; 1.
the low-affinity transporter Pho91 limits poly P accumulation in a strain lacking PHO85. This phenotype was not caused by a regulatory effect on the PHO pathway, but can be attributed to the unexpected localization of Pho91 in the vacuolar membrane.
Summary: The membrane location is supported by the multi-pass permease architecture independently of whether the resident membrane is plasma or vacuolar.
Summary: The supported Pho91 subfamily and characterized fungal phosphate transport justify phosphate transmembrane transporter activity rather than an unspecified solute.
the low-affinity transporter Pho91 limits poly P accumulation in a strain lacking PHO85. This phenotype was not caused by a regulatory effect on the PHO pathway, but can be attributed to the unexpected localization of Pho91 in the vacuolar membrane.
Summary: The phosphate substrate is supported by the SPX-Pho91 family assignment and primary characterization of its fungal relatives; phosphate ion transport is the more precise process.
the low-affinity transporter Pho91 limits poly P accumulation in a strain lacking PHO85. This phenotype was not caused by a regulatory effect on the PHO pathway, but can be attributed to the unexpected localization of Pho91 in the vacuolar membrane.
Summary: The phosphate substrate is supported by the SPX-Pho91 family assignment and primary characterization of its fungal relatives; phosphate ion transport is the more precise process.
the low-affinity transporter Pho91 limits poly P accumulation in a strain lacking PHO85. This phenotype was not caused by a regulatory effect on the PHO pathway, but can be attributed to the unexpected localization of Pho91 in the vacuolar membrane.
Core Functions
Predicted SPX-regulated phosphate transport by the Pho91-like membrane transporter.
the low-affinity transporter Pho91 limits poly P accumulation in a strain lacking PHO85. This phenotype was not caused by a regulatory effect on the PHO pathway, but can be attributed to the unexpected localization of Pho91 in the vacuolar membrane.
These computational predictions are reviewed separately from the GOA annotation set used for this review. The assessments below are from this project and do not constitute official GO annotations or endorsement by GO/UniProt. They are not included in the existing annotation review above.
Review rationale: The SPX-permease architecture and PANTHER Pho91 subfamily placement support phosphate transport by transfer from characterized fungal Pho87/Pho90/Pho91 transporters (PMID:17804816). The existing phosphate-transporter IBA is biologically supported and more specific than the prediction. The unresolved plasma versus vacuolar location does not undermine generic transmembrane transport.
PMID:17804816: "the low-affinity transporter Pho91 limits poly P accumulation in a strain lacking PHO85. This phenotype was not caused by a regulatory effect on the PHO pathway, but can be attributed to the unexpected localization of Pho91 in the vacuolar membrane."