syntaxin-binding protein 4 (syntaxin 4-interacting protein, STX4-interacting protein, Synip, STXBP4)

Function

• role in translocation of transport vesicles from cytoplasm to plasma membrane
• inhibits translocation of SLC2A4 from intracellular vesicles to plasma membrane by STX4A binding
• inhibits interaction between STX4A & VAMP2
• stimulation with insulin disrupts interaction of STXBP4 with STX4A, leading to SLC2A4 at the plasma membrane
• role in regulation of insulin release by pancreatic beta cells after stimulation by glucose (putative)
• insulin stimulates phosphorylation on Ser-99 by PKB/AKT2
  • phosphorylation on Ser-99 abolishes interaction with STX4A

Structure

• contains 1 PDZ domain (DHR) domain)
• contains 1 WW domain

Compartment

cytoplasm

Alternative splicing

named isoforms=2

More general terms

• UNC-18 homolog or syntaxin binding protein
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=252983
• UniProt: http://www.uniprot.org/uniprot/Q6ZWJ1.html