Immunogen sequence: EGVWPPPNNL LSQSPKKVTA ETDFNKSVDF EMPPPSPPLN LHELSGPAEG ASLTPKGGNP TKGLDTPGKR SVDKAVSVEA AERDWE Highest antigen sequence identity to the following orthologs: Mouse - 81%, Rat - 85%. Acts as a negative regulator of SRC by activating CSK