switch-associated protein 70 (SWAP-70, SWAP70, KIAA0640, HSPC321)

Function

• PIP3-dependent guanine nucleotide exchange factor
• transduces signals from tyrosine kinase receptors to RAC (RAS-independent)
• mediates signaling of membrane ruffling
• regulates actin cytoskeleton as an effector or adapter protein in response to agonist stimulated PIP2 production & cell protrusion
• component of SWAP complex
• Tyr-phosphorylated

Structure

• contains 1 PH domain
  • PH domain is essential for PIP3 binding

Compartment

• cytoplasm, cell membrane, nucleus
• in resting B-cells, localized mainly in cytoplasm, upon activation, recruited to plasma membrane, then translocates to the nucleus
• in activated, class-switching B-cells, associated with membrane IgG but not IgM
• localized to loose actin filament arrays located behind actively extending lamellipodia

Expression

• expressed only in mature B-cells including those associated with mucosa-associated tissue & bronchus-associated tissue
• widely expressed
• abundant in spleen, & fairly abundant in kidney, lung & liver
• also found in monocytes & macrophages

More general terms

• phosphoprotein
• guanine nucleotide exchange factor

Component of

• SWAP complex

Database

• OMIM: https://mirror.omim.org/entry/604762
• UniProt: http://www.uniprot.org/uniprot/Q9UH65.html