Centrin

Centrins, also known as caltractins, are a family of calcium-binding phosphoproteins found in the centrosome of eukaryotes. Centrins are small calcium binding proteins that are ubiquitous centrosome components. There are about 350 “signature” proteins that are unique to eukaryotic cells but have no significant homology to proteins in archaea and bacteria. They are a type of protein that is essential and present in almost all eukaryotic cells and are found in the centrioles and pericentriolar lattice. Human centrin genes are CETN1, CETN2 and CETN3^.

Humans and mice have three centrin genes: Cetn-1, which is typically only expressed in male germ cells, and Cetn-2 and Cetn-3, which are typically only expressed in somatic cells. Centrin-2 is a recombinant GFP-centrin-2 and centriole protein that localizes to centrioles throughout the cell cycle, while centrin-3 seems to stick to the pericentriolar material that surrounds the centrioles.