| Modification Notes |
SIRPs (signal-regulatory proteins) are a family of transmembrane glycoproteins that were identified by their association with the Src homology 2 domain-containing protein-tyrosine phosphatase SHP-2 in response to insulin. The SIRP family negatively regulates the PI 3-kinase pathway, which may diminish EGFR-mediated motility and survival phenotypes that contribute to transformation of certain cell types. SIRP-å1 is a transmembrane protein which acts as a substrate for activated receptor tyrosine kinases and, in its tyrosine phosphorylated form, binds to SH-PTP2 through SH2 interactions and acts as an SH-PTP2 substrate. SIRP-å1 has been shown to have negative regulatory effects on cellular responses induced by growth factors, oncogenes and Insulin. SIRP-∫1 shares extensive sequence homology with SIRP-å1 in its extracellular portion but lacks the cytoplasmic portion. SIRP-∫2 is a 342 amino acid multi-pass membrane protein that contains two Ig-like V-type (immunoglobulin-like) domains and exists as multiple alternatively spliced isoforms. |
