Q9VRR2 · S53A1_DROME
- ProteinSolute carrier family 53 member 1
- GenePXo
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids671 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Inorganic ion transporter that mediates phosphate ion export across the cell membrane (PubMed:37138087).
Plays a major role in phosphate homeostasis, preventing intracellular phosphate accumulation and possible calcium phosphate precipitation, ultimately preserving calcium signaling (PubMed:37138087).
The molecular mechanism of phosphate transport, whether electrogenic, electroneutral or coupled to other ions, remains to be elucidated (By similarity).
Binds inositol hexakisphosphate (Ins6P) and similar inositol polyphosphates, such as 5-diphospho-inositol pentakisphosphate (5-InsP7), important intracellular signaling molecules involved in regulation of phosphate flux (By similarity).
In enterocytes and differentiating progenitors of the gut, promotes the biogenesis and maintenance of organelles called PXo bodies that store intracellular inorganic phosphate (Pi), and also regulates Cka-JNK mediated tissue homeostasis in response to Pi availability in these tissues (PubMed:37138087).
Under conditions of adequate Pi, transports Pi into PXo bodies which convert and store the Pi in the form of phospholipids (PubMed:37138087).
It also inhibits Cka at the post-transcriptional level to prevent Cka-bsk/JNK mediated cell proliferation (PubMed:37138087).
Upon Pi starvation, Pxo expression is down-regulated resulting in the PXo bodies decreasing in phospholipid content until they undergo lysosomal/autophagosomal degradation and release the stored Pi back into the cytosol for use by the cell (PubMed:37138087).
Decrease in Pxo expression also activates the Cka protein, which moves to the nucleus to activate bsk/JNK which then induces nearby progenitor cells to proliferate and form new absorptive cells, probably helping the organism to cope with the nutrient deficiency by maximizing absorption of dietary Pi (PubMed:37138087).
Plays a major role in phosphate homeostasis, preventing intracellular phosphate accumulation and possible calcium phosphate precipitation, ultimately preserving calcium signaling (PubMed:37138087).
The molecular mechanism of phosphate transport, whether electrogenic, electroneutral or coupled to other ions, remains to be elucidated (By similarity).
Binds inositol hexakisphosphate (Ins6P) and similar inositol polyphosphates, such as 5-diphospho-inositol pentakisphosphate (5-InsP7), important intracellular signaling molecules involved in regulation of phosphate flux (By similarity).
In enterocytes and differentiating progenitors of the gut, promotes the biogenesis and maintenance of organelles called PXo bodies that store intracellular inorganic phosphate (Pi), and also regulates Cka-JNK mediated tissue homeostasis in response to Pi availability in these tissues (PubMed:37138087).
Under conditions of adequate Pi, transports Pi into PXo bodies which convert and store the Pi in the form of phospholipids (PubMed:37138087).
It also inhibits Cka at the post-transcriptional level to prevent Cka-bsk/JNK mediated cell proliferation (PubMed:37138087).
Upon Pi starvation, Pxo expression is down-regulated resulting in the PXo bodies decreasing in phospholipid content until they undergo lysosomal/autophagosomal degradation and release the stored Pi back into the cytosol for use by the cell (PubMed:37138087).
Decrease in Pxo expression also activates the Cka protein, which moves to the nucleus to activate bsk/JNK which then induces nearby progenitor cells to proliferate and form new absorptive cells, probably helping the organism to cope with the nutrient deficiency by maximizing absorption of dietary Pi (PubMed:37138087).
Catalytic activity
- phosphate(in) = phosphate(out)This reaction proceeds in the forward direction.
Features
Showing features for site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Site | 22 | Important for inositol polyphosphate binding | ||||
Sequence: Y | ||||||
Site | 26 | Important for inositol polyphosphate binding | ||||
Sequence: K |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytoplasm | |
Cellular Component | Golgi apparatus | |
Cellular Component | organelle membrane | |
Cellular Component | plasma membrane | |
Molecular Function | inositol hexakisphosphate binding | |
Molecular Function | phosphate transmembrane transporter activity | |
Biological Process | cellular response to phosphate starvation | |
Biological Process | intracellular phosphate ion homeostasis | |
Biological Process | negative regulation of cell population proliferation | |
Biological Process | negative regulation of JUN kinase activity | |
Biological Process | phosphate ion transport | |
Biological Process | regulation of cellular response to phosphate starvation |
Keywords
- Biological process
Names & Taxonomy
Protein names
- Recommended nameSolute carrier family 53 member 1
- Alternative names
Gene names
Organism names
- Strain
- Taxonomic lineageEukaryota > Metazoa > Ecdysozoa > Arthropoda > Hexapoda > Insecta > Pterygota > Neoptera > Endopterygota > Diptera > Brachycera > Muscomorpha > Ephydroidea > Drosophilidae > Drosophila > Sophophora
Accessions
- Primary accessionQ9VRR2
Proteomes
Organism-specific databases
Subcellular Location
UniProt Annotation
GO Annotation
Membrane ; Multi-pass membrane protein
Note: Localizes to the membrane of multi-membrane-layered organelles called PXo bodies, that function as intracellular reserves of inorganic phosphate stored in the form of phospholipids.
Features
Showing features for topological domain, transmembrane.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Topological domain | 1-228 | Cytoplasmic | ||||
Sequence: MKFAEHLTAHITPEWRKQYINYEEMKAMLYAAIEQSPSAELVEREMVTRYFAKFDEEFFHYCDKELAKINTFYSEKMAEATRKYGSLRSELTEALEMGHPKKLPAWKRRTPLGKKNVPARKIQDLKLAFSEFYLGLILLQNYQNLNFTGFRKILKKHDKLLSVDYGARWRTDHVEAAHFYTNKDIDRLIQETEQAVTQDIEGGDRQRAMKRLRVPPLGEQQSPWTTFK | ||||||
Transmembrane | 229-249 | Helical | ||||
Sequence: VGLFSGAFVVLFITVVIAAMF | ||||||
Topological domain | 250-262 | Extracellular | ||||
Sequence: YGFGENWRAGMRM | ||||||
Transmembrane | 263-283 | Helical | ||||
Sequence: FRAPFLIIECLFLWGVNVYGW | ||||||
Topological domain | 284-306 | Cytoplasmic | ||||
Sequence: RSSGVNHVLIFELDPRNHLSEQN | ||||||
Transmembrane | 307-327 | Helical | ||||
Sequence: IMEVASVFGVIWACCVLSYIF | ||||||
Topological domain | 328-330 | Extracellular | ||||
Sequence: CDP | ||||||
Transmembrane | 331-351 | Helical | ||||
Sequence: LGIPQYAAPLCLYTLMAAFLL | ||||||
Topological domain | 352-367 | Cytoplasmic | ||||
Sequence: NPTKTFHHEARFWAIR | ||||||
Transmembrane | 368-388 | Helical | ||||
Sequence: ILIRVIMAPFCFVNFADFWLA | ||||||
Transmembrane | 389-409 | Helical | ||||
Sequence: DQLNSMVPAFLDIPFLICFFG | ||||||
Topological domain | 410-421 | Cytoplasmic | ||||
Sequence: RSPTWHKAGKAA | ||||||
Transmembrane | 422-442 | Helical | ||||
Sequence: SHCVEYVSLLHPIVAIMPAYF | ||||||
Topological domain | 443-456 | Extracellular | ||||
Sequence: RFAQCIRRYRDTKE | ||||||
Transmembrane | 457-477 | Helical | ||||
Sequence: SFPHLVNAAKYATSFFVVIFA | ||||||
Topological domain | 478-494 | Cytoplasmic | ||||
Sequence: HKYHTTTDTYPLSKENP | ||||||
Transmembrane | 495-515 | Helical | ||||
Sequence: WFYCWITAAIFSSCYAYTWDI | ||||||
Topological domain | 516-535 | Extracellular | ||||
Sequence: KMDWGLFDSKAGDNRFLREE | ||||||
Transmembrane | 536-556 | Helical | ||||
Sequence: IVYSSTWFYYFGIIEDLILRF | ||||||
Topological domain | 557-671 | Cytoplasmic | ||||
Sequence: SWTLSMSLIEAGYIEGDVMMTILSPLEVFRRFIWNYFRLENEHLNNVGKFRAVRDISVAPMDCSDQTTILRMMDETDGVLNRRRGKAAGGKSATKKNKQEQRLLLQGESIEDLCS |
Keywords
- Cellular component
Phenotypes & Variants
Disruption phenotype
RNAi-mediated knockdown results in various phenotypes that also occur in flies undergoing inorganic phosphate starvation, including activation of midgut hyperproliferation and activation of cell mitosis (PubMed:37138087).
RNAi-mediated knockdown in either enterocytes or progenitors, induces mitosis under both under normal conditions and with bleomycin-induced tissue damage (PubMed:37138087).
Enterocytes but not progenitors, display increased levels of cytosolic inorganic phosphate (PubMed:37138087).
RNAi-mediated knockdown in enterocytes does not result in an increase in apoptosis (PubMed:37138087).
RNAi-mediated knockdown in either enterocytes or progenitors, induces mitosis under both under normal conditions and with bleomycin-induced tissue damage (PubMed:37138087).
Enterocytes but not progenitors, display increased levels of cytosolic inorganic phosphate (PubMed:37138087).
RNAi-mediated knockdown in enterocytes does not result in an increase in apoptosis (PubMed:37138087).
Features
Showing features for mutagenesis.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Mutagenesis | 1-193 | Not affected by phosphonoformic acid (PFA). | ||||
Sequence: Missing |
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000458750 | 1-671 | Solute carrier family 53 member 1 | |||
Sequence: MKFAEHLTAHITPEWRKQYINYEEMKAMLYAAIEQSPSAELVEREMVTRYFAKFDEEFFHYCDKELAKINTFYSEKMAEATRKYGSLRSELTEALEMGHPKKLPAWKRRTPLGKKNVPARKIQDLKLAFSEFYLGLILLQNYQNLNFTGFRKILKKHDKLLSVDYGARWRTDHVEAAHFYTNKDIDRLIQETEQAVTQDIEGGDRQRAMKRLRVPPLGEQQSPWTTFKVGLFSGAFVVLFITVVIAAMFYGFGENWRAGMRMFRAPFLIIECLFLWGVNVYGWRSSGVNHVLIFELDPRNHLSEQNIMEVASVFGVIWACCVLSYIFCDPLGIPQYAAPLCLYTLMAAFLLNPTKTFHHEARFWAIRILIRVIMAPFCFVNFADFWLADQLNSMVPAFLDIPFLICFFGRSPTWHKAGKAASHCVEYVSLLHPIVAIMPAYFRFAQCIRRYRDTKESFPHLVNAAKYATSFFVVIFAHKYHTTTDTYPLSKENPWFYCWITAAIFSSCYAYTWDIKMDWGLFDSKAGDNRFLREEIVYSSTWFYYFGIIEDLILRFSWTLSMSLIEAGYIEGDVMMTILSPLEVFRRFIWNYFRLENEHLNNVGKFRAVRDISVAPMDCSDQTTILRMMDETDGVLNRRRGKAAGGKSATKKNKQEQRLLLQGESIEDLCS |
Proteomic databases
Expression
Tissue specificity
Detected in PXo bodies found in the enterocytes and progenitors of the midgut and in the hindgut, but rarely occur in the Malpighian tubules, crop, brain, muscles and germlines (at protein level).
Induction
Down-regulated in the midgut following inorganic phosphate starvation.
Gene expression databases
Structure
Family & Domains
Features
Showing features for domain, region.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Domain | 1-171 | SPX | ||||
Sequence: MKFAEHLTAHITPEWRKQYINYEEMKAMLYAAIEQSPSAELVEREMVTRYFAKFDEEFFHYCDKELAKINTFYSEKMAEATRKYGSLRSELTEALEMGHPKKLPAWKRRTPLGKKNVPARKIQDLKLAFSEFYLGLILLQNYQNLNFTGFRKILKKHDKLLSVDYGARWRT | ||||||
Region | 1-193 | Important for promoting lysosomal/autophagosomal degradation of PXo bodies following inorganic phosphate (Pi) starvation | ||||
Sequence: MKFAEHLTAHITPEWRKQYINYEEMKAMLYAAIEQSPSAELVEREMVTRYFAKFDEEFFHYCDKELAKINTFYSEKMAEATRKYGSLRSELTEALEMGHPKKLPAWKRRTPLGKKNVPARKIQDLKLAFSEFYLGLILLQNYQNLNFTGFRKILKKHDKLLSVDYGARWRTDHVEAAHFYTNKDIDRLIQETE | ||||||
Region | 152-159 | Important for inositol polyphosphate binding | ||||
Sequence: KILKKHDK | ||||||
Domain | 423-627 | EXS | ||||
Sequence: HCVEYVSLLHPIVAIMPAYFRFAQCIRRYRDTKESFPHLVNAAKYATSFFVVIFAHKYHTTTDTYPLSKENPWFYCWITAAIFSSCYAYTWDIKMDWGLFDSKAGDNRFLREEIVYSSTWFYYFGIIEDLILRFSWTLSMSLIEAGYIEGDVMMTILSPLEVFRRFIWNYFRLENEHLNNVGKFRAVRDISVAPMDCSDQTTILR |
Domain
The SPX domain has high affinity for inositol polyphosphates, such as myo-inositol hexakisphosphate and 5-diphospho-myo-inositol pentakisphosphate (5-InsP7) (By similarity).
Its affinity for inorganic phosphate is two to three orders of magnitude lower (By similarity).
Its affinity for inorganic phosphate is two to three orders of magnitude lower (By similarity).
Sequence similarities
Belongs to the SYG1 (TC 2.A.94) family.
Keywords
- Domain
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length671
- Mass (Da)78,202
- Last updated2000-05-01 v1
- ChecksumD1BEE3C2FCBC8D96
Computationally mapped potential isoform sequences
There is 1 potential isoform mapped to this entry
Entry | Entry name | Gene name | Length | ||
---|---|---|---|---|---|
A0A4D6K4X7 | A0A4D6K4X7_DROME | PXo | 606 |
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
AE014296 EMBL· GenBank· DDBJ | AAF50730.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AY051618 EMBL· GenBank· DDBJ | AAK93042.1 EMBL· GenBank· DDBJ | mRNA |