Protein: Vacuolar transporter chaperone complex subunit 1 (Negative regulator of cdc42) (SPX-dependent polyphosphate polymerase VTC subunit 1) (Vacuolar membrane polyphosphate polymerase accessory subunit 1) (PolyP polymerase) (Q9UR17)
Organism: Schizosaccharomyces pombe (strain 972 / ATCC 24843) (Fission yeast)
Function: Accessory subunit of the vacuolar transporter chaperone (VTC) complex. The VTC complex acts as vacuolar polyphosphate polymerase that catalyzes the synthesis of inorganic polyphosphate (polyP) via transfer of phosphate from ATP to a growing polyP chain, releasing ADP. VTC exposes its catalytic domain vtc4 to the cytosol, where the growing polyP chain winds through a tunnel-shaped pocket, integrating cytoplasmic polymer synthesis with polyP membrane translocation. The VTC complex carries 9 vacuolar transmembrane domains, which are likely to constitute the translocation channel into the organelle lumen. PolyP synthesis is tightly coupled to its transport into the vacuole lumen, in order to avoid otherwise toxic intermediates in the cytosol, and it depends on the proton gradient across the membrane, formed by V-ATPase. Vtc1 contributes only 3 transmembrane domains to the complex. The VTC complex also plays a role in vacuolar membrane fusion (By similarity). Involved in the control of cell polarity.
Subcellular location: Vacuole membrane {ECO:0000269|PubMed:10628977, ECO:0000269|PubMed:11042180}; Multi-pass membrane protein {ECO:0000255}.
InterPro domains:
- IPR051572: Vacuolar Transporter Chaperone Complex Subunit (family) [7-120]
- IPR003807: Domain of unknown function DUF202 (domain) [24-85]
Sequence:
MSTQPLLQTTPGKRIALPVRVEPKVFFANERTFLSWLSFAVVLGGLSVGLLNFGDRIGKISAGLFTIVAIGTMGYALGIYHWRASAIRRRGSGPYDDRLGPTILCFVLLAAIITNFVLRMLF
Predicted GO terms:
Molecular Function (MF): GO:0003674 (molecular function), GO:0005488 (binding), GO:0005515 (protein binding)
Biological Process (BP): GO:0008150 (biological process), GO:0008152 (metabolic process), GO:0009987 (cellular process), GO:0051179 (localization), GO:0051234 (establishment of localization), GO:0051641 (cellular localization), GO:0071840 (cellular component organization or biogenesis), GO:0009058 (biosynthetic process), GO:0044237 (cellular metabolic process), GO:0061919 (process utilizing autophagic mechanism), GO:0071704 (organic substance metabolic process), GO:0044281 (small molecule metabolic process), GO:0009056 (catabolic process), GO:0051649 (establishment of localization in cell), GO:0016043 (cellular component organization), GO:0044249 (cellular biosynthetic process), GO:0046907 (intracellular transport), GO:0006082 (organic acid metabolic process), GO:0044248 (cellular catabolic process), GO:0006810 (transport), GO:0006914 (autophagy), GO:0006793 (phosphorus metabolic process), GO:0006797 (polyphosphate metabolic process), GO:0016237 (lysosomal microautophagy), GO:0007034 (vacuolar transport), GO:0006996 (organelle organization), GO:0043436 (oxoacid metabolic process), GO:0048284 (organelle fusion), GO:0007033 (vacuole organization), GO:0097576 (vacuole fusion), GO:0042144 (vacuole fusion, non-autophagic)
Cellular Component (CC): GO:0005575 (cellular component), GO:0110165 (cellular anatomical entity), GO:0005622 (intracellular anatomical structure), GO:0043226 (organelle), GO:0016020 (membrane), GO:0005737 (cytoplasm), GO:0012505 (endomembrane system), GO:0005794 (Golgi apparatus), GO:0005773 (vacuole), GO:0031090 (organelle membrane), GO:0005783 (endoplasmic reticulum), GO:0043229 (intracellular organelle), GO:0043227 (membrane-bounded organelle), GO:0000323 (lytic vacuole), GO:0043231 (intracellular membrane-bounded organelle), GO:0005774 (vacuolar membrane), GO:0098588 (bounding membrane of organelle), GO:0000322 (storage vacuole), GO:0000324 (fungal-type vacuole), GO:0098852 (lytic vacuole membrane), GO:0000329 (fungal-type vacuole membrane)