Chimerin
Chimerin is a type of nerve tissue protein. Chimerins are a family of non-PKC phorbol-ester receptors. They were the first to be discovered within this family. The name stems from their resemblance to the "chimera." There are four known isoforms of the Chimerin protein. These include α1, α2, β1, and β2. α1-Chimerin was the first protein to be isolated from the brain. The other domains were discovered through alternative splicing. The α and β isoforms are almost identical, the key difference stems from the SH2 domain at the N-terminal. α1-Chimerin is a GTPase-activating  protein in the brain that effects the ras related p21rac. α1-Chimerin is also able to regulate dendritic spinal density by binding to NMDA receptors at the NR2A subunit. Over expression of this protein in hippocampus tissue can inhibit the formation of new spines and remove existing spines. α2-Chimerin acts in a similar manner to α1-Chimerin, but is primarily found in the brain and testes. It is also an SH2 containing GTPase activating protein and bears many similarities in function. It Is derived from alternative splicing of the α-Chimera gene. β2-chimerin has been shown to play  a role in breast cancer. In breast cancer cells the amount of β2-chimerin messengers are extremely low. When introduced to the cancerous cells β2-chimerin then causes the G1 cell cycle  to stop and therefore it stops the cells from multiplying. β2-chimerin can be linked to a fusion gene that is associated with a key insulin receptor that causes people to have decreased levels of insulin.