Protein: Vacuolar transporter chaperone complex subunit 2 (SPX-dependent polyphosphate polymerase VTC subunit 2) (Vacuolar membrane polyphosphate polymerase accessory subunit 2) (PolyP polymerase) (O13718)
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. The VTC complex also plays a role in vacuolar membrane fusion.
Subcellular location: Vacuole membrane {ECO:0000250|UniProtKB:P43585}; Multi-pass membrane protein {ECO:0000255}.
Sequence: MRFSDSIEAGIYEPWRDKYMNYPELKHLLKTEEEAPSWGENDESKFVSVMDAQLEKVYAFHLEILKELNESVDWVKSKVSASQEPDGPPISKEEAIKLLERLDSCTETVKKLEKYTRLNLTGFFKIVKKHDKLYPGYSLRPVFQVRLRACPLGSVQFNPLLAEIFSLYNTLRDGLSAPSNSVQVKPKHEHNVDYNSSMYRRRTFRFWVHPDNVMEVKTYIMRHLPVLYYSGKQGFDKDQNGVSGILDPISTCLYLDNSNFDLYSQNLERSEQAYSLRLHWYGKLTPKTDIIVERMVRQGSTLSHSEDRFTIREKKVRELLSGRYDFRKVEDDHSTTASDQKKKLIEDVEQLIVDNHLQPVLRSVYTRTAFQIPGDDEVRINLDSDWVMIREDSLDIERPCRDPEDWHRHDIDDADFPYKHLRKGEYSRFPYSVLEIRECVRYDEDEPLWISELRNSHLISEIDGFSKYEHGVAILFEKYVSLLPMWVFSMDQDIRKDLQEVYSHPEGSAGSRNVYIKRRNQRVLKQNMTPEPSQPSPLVNRLKANEMHPVSEEPEDNREVYRNEHGDHFNFRSIPGLLKPSTYGSFKHHGKTFVTPPHIKKPEIPLRVSGPIKVEAKVWLANERTFLKWLHVVVLLGSLALALYNSAGERLGQAFGVVYTLLAIFIGFYAWKLHAKRSQMIKSRSPAPMTDYWGPLIVGTALAISLIVNMSFALKDAVYQNLIEPDRLLVKLFT
InterPro domains: - IPR003807: Domain of unknown function DUF202 (domain) [617-679]
- IPR042267: VTC domain superfamily (homologous_superfamily) [193-488]
- IPR004331: SPX domain (domain) [1-144]
- IPR051572: Vacuolar Transporter Chaperone Complex Subunit (family) [1-717]
- IPR018966: VTC domain (domain) [201-476]
Interaction partners: - Vacuolar transporter chaperone complex subunit 4
- Glycerophosphocholine phosphodiesterase gde1
- Vacuolar transporter chaperone complex subunit 1
- Uncharacterized RING finger protein C6B12.07c
- Putative inorganic phosphate transporter C8E4.01c
- Serine O-succinyltransferase
- Uncharacterized transporter C3B8.04c
- T-complex protein 1 subunit alpha
- Putative inorganic phosphate transporter C23D3.12
- Probable T-complex protein 1 subunit eta
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0005488 (binding), GO:0036094 (small molecule binding), GO:0043167 (ion binding), GO:0005515 (protein binding), GO:0043168 (anion binding), GO:0043178 (alcohol binding), GO:0005516 (calmodulin binding)
Biological Process (BP): GO:0008150 (biological process), GO:0065007 (biological regulation), GO:0051179 (localization), GO:0050896 (response to stimulus), GO:0050789 (regulation of biological process), GO:0009987 (cellular process), GO:0023052 (signaling), GO:0051641 (cellular localization), GO:0019222 (regulation of metabolic process), GO:0050794 (regulation of cellular process), GO:0051234 (establishment of localization), GO:0051716 (cellular response to stimulus), GO:0071840 (cellular component organization or biogenesis), GO:0007154 (cell communication), GO:0007165 (signal transduction), GO:0033036 (macromolecule localization), GO:0046907 (intracellular transport), GO:0035556 (intracellular signal transduction), GO:0006810 (transport), GO:0009889 (regulation of biosynthetic process), GO:0070727 (cellular macromolecule localization), GO:0051649 (establishment of localization in cell), GO:0016043 (cellular component organization), GO:0031323 (regulation of cellular metabolic process), GO:0080090 (regulation of primary metabolic process), GO:0045184 (establishment of protein localization), GO:0006886 (intracellular protein transport), GO:0071705 (nitrogen compound transport), GO:0010556 (regulation of macromolecule biosynthetic process), GO:0015031 (protein transport), GO:0031326 (regulation of cellular biosynthetic process), GO:0071702 (organic substance transport), GO:0006109 (regulation of carbohydrate metabolic process), GO:0008104 (protein localization), GO:0007264 (small GTPase mediated signal transduction), GO:0006996 (organelle organization), GO:0019932 (second-messenger-mediated signaling), GO:0035220 (wing disc development), GO:0033365 (protein localization to organelle), GO:0072666 (establishment of protein localization to vacuole), GO:0007033 (vacuole organization), GO:0006605 (protein targeting), GO:0006623 (protein targeting to vacuole), GO:0019722 (calcium-mediated signaling), GO:0034504 (protein localization to nucleus), GO:0072665 (protein localization to vacuole)
Cellular Component (CC): GO:0005575 (cellular component), GO:0110165 (cellular anatomical entity), GO:0005622 (intracellular anatomical structure), GO:0043226 (organelle), GO:0005737 (cytoplasm), GO:0012505 (endomembrane system), GO:0043229 (intracellular organelle), GO:0005783 (endoplasmic reticulum), GO:0043227 (membrane-bounded organelle), GO:0043231 (intracellular membrane-bounded organelle)