SH2 Domain Antibodies

Src homology domains are portions of small binding proteins found in Src oncoproteins. Src is an enzyme encoded by the SRC gene. SRC (pronounced “SARC”) is a cancer gene that contains the code for a tyrosine kinase that plays an important role in the formation of sarcomas and other cancers when the normal cellular signals fail to function. The SH2 domain contains approximately 100 amino acids and regulates the protein tyrosine kinase activity in the carboxy- terminal half of the src protein. The SH2 domain is involved in many intracellular signal-transducing actions and it helps the Src protein to bind to other proteins. These protein to protein interactions are very important in cellular growth. The proteins themselves are composed of amino acids in a chain that can bend and fold into different conformational shapes. These shapes then can bind to one another (among other molecules) depending on their shape, polarity, and other affinity characteristics. Anti- SH2 antibodies recognize these proteins and can interact with them to prevent, enhance, or otherwise affect their mechanism of action. The function of the SH2 domains is to seek out tyrosine residues that have been phosphorylated. The SH2 proteins can then bind to its preferred site and transmit a signal through a membrane.

The anti-RAN antibody binds to the protein target RAN. RAN is a protein (GTPase enzyme) that binds GTP and is involved in nucleocytoplasmic transport. More specifically, it assists in the import of protein into the nucleus of a cell which is used for RNA transportation. It has roles in cell cycle control by condensing chromatin. RAN also affects many other cellular processes inadvertently. Different mutations of RAN can occur which lead to defects in nuclear protein import. The anti-BCAR3 antibody targets the BCAR3 protein. Breast cancer anti-estrogen resistance protein 3 takes part in intracellular signal transduction. It contains one src homology 2 (SH2) domain. Defects in BCAR3 cause estrogen-independent proliferation in human breast cancer cells. Breast cancer cells are extremely dependent on estrogen to grow. Anti-estrogens like tamoxifen are useful in inhibiting breast cancer. The cancer, however, has been known to become resistant to anti-estrogens in treatment. The BCAR3 gene has been found to encode for the manufacture of the protein that causes estrogen-independent proliferation in human breast cancer cells.