Q9VRR2 · S53A1_DROME

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).

Catalytic activity

Features

Showing features for site.

TypeIDPosition(s)Description
Site22Important for inositol polyphosphate binding
Site26Important for inositol polyphosphate binding

GO annotations

AspectTerm
Cellular Componentcytoplasm
Cellular ComponentGolgi apparatus
Cellular Componentorganelle membrane
Cellular Componentplasma membrane
Molecular Functioninositol hexakisphosphate binding
Molecular Functionphosphate transmembrane transporter activity
Biological Processcellular response to phosphate starvation
Biological Processintracellular phosphate ion homeostasis
Biological Processnegative regulation of cell population proliferation
Biological Processnegative regulation of JUN kinase activity
Biological Processphosphate ion transport
Biological Processregulation of cellular response to phosphate starvation

Keywords

Names & Taxonomy

Protein names

  • Recommended name
    Solute carrier family 53 member 1
  • Alternative names
    • Inorganic phosphate-sensitive XPR1 homolog
    • Phosphate exporter PXo
    • Xenotropic and polytropic retrovirus receptor 1

Gene names

    • Name
      PXo
    • Synonyms
      XPR1
    • ORF names
      CG10483

Organism names

  • Taxonomic identifier
  • Strain
    • Berkeley
  • Taxonomic lineage
    Eukaryota > Metazoa > Ecdysozoa > Arthropoda > Hexapoda > Insecta > Pterygota > Neoptera > Endopterygota > Diptera > Brachycera > Muscomorpha > Ephydroidea > Drosophilidae > Drosophila > Sophophora

Accessions

  • Primary accession
    Q9VRR2

Proteomes

Organism-specific databases

Subcellular Location

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.

TypeIDPosition(s)Description
Topological domain1-228Cytoplasmic
Transmembrane229-249Helical
Topological domain250-262Extracellular
Transmembrane263-283Helical
Topological domain284-306Cytoplasmic
Transmembrane307-327Helical
Topological domain328-330Extracellular
Transmembrane331-351Helical
Topological domain352-367Cytoplasmic
Transmembrane368-388Helical
Transmembrane389-409Helical
Topological domain410-421Cytoplasmic
Transmembrane422-442Helical
Topological domain443-456Extracellular
Transmembrane457-477Helical
Topological domain478-494Cytoplasmic
Transmembrane495-515Helical
Topological domain516-535Extracellular
Transmembrane536-556Helical
Topological domain557-671Cytoplasmic

Keywords

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).

Features

Showing features for mutagenesis.

TypeIDPosition(s)Description
Mutagenesis1-193Not affected by phosphonoformic acid (PFA).

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00004587501-671Solute carrier family 53 member 1

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

Interaction

Subunit

Interacts with the FAR/SIN/STRIPAK complex members Cka and Pp2A-29B.

Protein-protein interaction databases

Structure

Family & Domains

Features

Showing features for domain, region.

TypeIDPosition(s)Description
Domain1-171SPX
Region1-193Important for promoting lysosomal/autophagosomal degradation of PXo bodies following inorganic phosphate (Pi) starvation
Region152-159Important for inositol polyphosphate binding
Domain423-627EXS

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).

Sequence similarities

Belongs to the SYG1 (TC 2.A.94) family.

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    671
  • Mass (Da)
    78,202
  • Last updated
    2000-05-01 v1
  • Checksum
    D1BEE3C2FCBC8D96
MKFAEHLTAHITPEWRKQYINYEEMKAMLYAAIEQSPSAELVEREMVTRYFAKFDEEFFHYCDKELAKINTFYSEKMAEATRKYGSLRSELTEALEMGHPKKLPAWKRRTPLGKKNVPARKIQDLKLAFSEFYLGLILLQNYQNLNFTGFRKILKKHDKLLSVDYGARWRTDHVEAAHFYTNKDIDRLIQETEQAVTQDIEGGDRQRAMKRLRVPPLGEQQSPWTTFKVGLFSGAFVVLFITVVIAAMFYGFGENWRAGMRMFRAPFLIIECLFLWGVNVYGWRSSGVNHVLIFELDPRNHLSEQNIMEVASVFGVIWACCVLSYIFCDPLGIPQYAAPLCLYTLMAAFLLNPTKTFHHEARFWAIRILIRVIMAPFCFVNFADFWLADQLNSMVPAFLDIPFLICFFGRSPTWHKAGKAASHCVEYVSLLHPIVAIMPAYFRFAQCIRRYRDTKESFPHLVNAAKYATSFFVVIFAHKYHTTTDTYPLSKENPWFYCWITAAIFSSCYAYTWDIKMDWGLFDSKAGDNRFLREEIVYSSTWFYYFGIIEDLILRFSWTLSMSLIEAGYIEGDVMMTILSPLEVFRRFIWNYFRLENEHLNNVGKFRAVRDISVAPMDCSDQTTILRMMDETDGVLNRRRGKAAGGKSATKKNKQEQRLLLQGESIEDLCS

Computationally mapped potential isoform sequences

There is 1 potential isoform mapped to this entry

View all
EntryEntry nameGene nameLength
A0A4D6K4X7A0A4D6K4X7_DROMEPXo606

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AE014296
EMBL· GenBank· DDBJ
AAF50730.1
EMBL· GenBank· DDBJ
Genomic DNA
AY051618
EMBL· GenBank· DDBJ
AAK93042.1
EMBL· GenBank· DDBJ
mRNA

Genome annotation databases

Similar Proteins

Disclaimer

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