caveolin-2 (CAV2)

Function

• may act as a scaffolding protein within caveolar membranes
• interacts directly with G-protein alpha subunits & can functionally regulate their activity
• acts as an accessory protein in conjunction with CAV1 in targeting to lipid rafts & driving caveolae formation
• Ser-36 phosphorylated form has a role in modulating mitosis in endothelial cells
• positive regulator of cellular mitogenesis of the MAPK signaling pathway
• required for the insulin-stimulated nuclear translocation & activation of MAPK1 & STAT3, & the subsequent regulation of cell cycle progression (putative)
• may be involved in synaptic transduction in the retina
• phosphorylated on Ser & Tyr
• CAV1 promotes phosphorylation on Ser-23 which then targets the complex to the plasma membrane, lipid rafts & caveolae
• phosphorylation on Ser-36 appears to modulate mitosis in endothelial cells
• phosphorylation on both Tyr-19 & Tyr-27 is required for insulin-induced Ser-727 phosphorylation of STAT3 & its activation
  • phosphorylation on Tyr-19 is required for insulin-induced phosphorylation of MAPK1 & DNA binding of STAT3
• tyrosine phosphorylation is induced by both EGF & insulin
• interacts with CAV1; the interaction forms a stable heterooligomeric complex required for targeting to lipid rafts & for caveolae formation
• Tyr phosphorylated forms do not form heterooligomers;
  • Tyr-19-phosphorylated form exiss as a monomer or dimer
  • Tyr-27-form exists as a monomer only
  • Tyr phosphorylated form interacts with the SH2 domain containing proteins, RASA1, NCK1 & SRC
  • Tyr phosphorylated form interacts with INSR
    • interaction of Tyr-27-phosphorylated form is increased on insulin stimulation
  • Tyr-19 phosphorylated form interacts with phosphorylated MAPK1
    • the interaction promoted by insulin, leads to nuclear location & MAPK1 activation
• interacts with STAT3
  • interaction is increased on insulin-induced Tyr phosphorylation leading to STAT activation (putative)

Structure

• monomer or homodimer
• belongs to the caveolin family

Compartment

• nucleus, cytoplasm, Golgi membrane
• cell membrane, caveola
• potential hairpin-like structure in the membrane
• membrane protein of caveolae
• Tyr-19-phosphorylated form is enriched at sites of cell-cell contact & is translocated to the nucleus in complex with MAPK1 in response to insulin (putative)
• Tyr-27-phosphorylated form is located both in the cytoplasm & plasma membrane
• CAV1-mediated Ser-23-phosphorylated form locates to the plasma membrane
• Ser-36-phosphorylated form resides in intracellular compartments

Alternative initiation

• named isoforms=3; alpha, beta, C
• alternative splicing

Expression

• expressed in endothelial cells, smooth muscle cells, skeletal myoblasts & fibroblasts

More general terms

• caveolin
• nuclear protein
• phosphoprotein

Additional terms

• caveola

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=858
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:858
• OMIM: https://mirror.omim.org/entry/601048
• UniProt: http://www.uniprot.org/uniprot/P51636.html