phosphoprotein associated with glycosphingolipid-enriched microdomains 1 (transmembrane adapter protein PAG, Csk-binding protein, transmembrane phosphoprotein Cbp, PAG1, CBP, PAG)

Function

• negatively regulates TCR-mediated signaling in T-cells & FCER1-mediated signaling in mast cells
• promotes CSK activation & recruitment to lipid rafts, resulting in LCK inhibition
• inhibits immunological synapse formation by preventing dynamic arrangement of lipid raft proteins.
• role in cell adhesion signaling (putative)
• interacts with FYN
  • phosphorylated by FYN on Tyr-317 in resting T-cells, which promotes interaction with CSK
• when phosphorylated, interacts with CSK
• dephosphorylated by PTPRC/CD45 upon TCR activation; which leads to CSK dissociatio
• may also be dephosphorylated by PTPN11
• hyperphosphorylated in mast cells upon FCER1 activation
• interacts with SLC9A3R1/EBP50
• in resting T-cells, part of a PAG1-SLC9A3R1-MSN complex which is disrupted upon TCR activation

Structure

palmitoylated

Compartment

cell membrane, present in lipid rafts

Expression

• ubiquitously expressed
• present in germinal center B-cells, plasma cells, T-cells, monocytes & platelets (at protein level)

More general terms

• membrane protein
• phosphoprotein

Database

• OMIM: https://mirror.omim.org/entry/605767
• UniProt: http://www.uniprot.org/uniprot/Q9NWQ8.html