The Src kinase family is a class of non-receptor tyrosine kinases that contains nine members: Src, Yes, Fyn, and Fgr, forming the SrcA subfamily in the SrcB subfamily, Lck, Hck, Blk, and Lyn, in their own Frk is formed in the subfamily. Frk has homologs in invertebrates such as flies and helminths, and Src homologs are present in organisms that differ from single-celled flagellates, but the SrcA and SrcB subfamilies are specific to vertebrates. The Src family kinase contains six conserved domains: the N-terminal myristoylation fragment, the SH2 domain, the SH3 domain, the linker region, the tyrosine kinase domain, and the C-terminal tail. Src family kinases interact with many cellular cytoplasmic, nuclear and membrane proteins to modify these proteins by phosphorylation of tyrosine residues. Many substrates for these enzymes have been discovered. Disorders, including constitutive activation or overexpression, may contribute to the progression of cell transformation and carcinogenic activity.
Proto-oncogene tyrosine-protein kinase Src
The proto-oncogene tyrosine protein kinase Src, also known as the proto-oncogene c-Src or simply c-Src, is a non-receptor tyrosine kinase protein encoded by the Src gene in humans. This protein phosphorylates specific tyrosine residues in other tyrosine kinases. c-Src stands for "cell Src kinase" and should not be confused with "C-terminal Src kinase" (CSK), a negatively regulated enzyme that phosphorylates c-Src at its C-terminus and provides Src enzyme activity. Similarly, c-Src should not be mistaken for v-Src, a virus (and hence the prefix v-) gene that is similar to c-Src, and an oncogene that can be found in the Rous sarcoma virus. It is suggested that elevated levels of c-Src tyrosine kinase activity are associated with cancer progression by promoting other signals. Mutations in this gene may be associated with malignant progression of colon cancer. This proto-oncogene may play a role in the regulation of embryonic development and cell growth. c-Src includes the SH2 domain, the SH3 domain, and the tyrosine kinase domain. Src (pronounced "sarc" because it is an abbreviation for sarcoma) was originally discovered by J. Michael Bishop and Harold E. Varmus, so they were awarded the 1989 Nobel Prize in Physiology or Medicine. It belongs to the Src family of kinase families. This gene is similar to the v-Src gene of Rous sarcoma virus. This gene has been found to encode two transcriptional variants of the same protein.
This proto-oncogene may play a role in the regulation of embryonic development and cell growth. When src is activated, it promotes survival, angiogenesis, proliferation and invasion pathways. It also regulates angiogenic factors and vascular permeability after focal cerebral ischemia and reperfusion, and regulates matrix metalloproteinase-9 activity following cerebral hemorrhage.
As a drug target
A number of tyrosine kinase inhibitors targeting c-Src tyrosine kinases (and related tyrosine kinases) have been developed for therapeutic use. A notable example is dasatinib, which has been approved for the treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome positive (PH+) acute lymphoblastic leukemia (ALL). Dasatinib is also used in clinical trials for non-Hodgkin's lymphoma, metastatic breast cancer and prostate cancer. Other tyrosine kinase inhibitor drugs in clinical trials include bosutinib, bafetinib, AZD-530, XL1-999, KX01 and XL228.
1. Zhao X.; et al. Toxic role of prostaglandin E2 receptor EP1 after intracerebral hemorrhage in mice. Brain Behav. Immun. 2015, 46: 293-310.
2. Parsons SJ.; et al. Src family kinases, key regulators of signal transduction. Oncogene. 2004,23 (48): 7906-9.