Centrin 2 (CETN2)

Caltractin, a 20-kD calcium-binding protein, was purified and cloned at the DNA level from the unicellular green alga Chlamydomonas. It showed a strong amino acid sequence relatedness (50%) to the CDC31 gene product from Saccharomyces cerevisiae. Examination of mutants in Chlamydomonas caltractin and yeast CDC31 indicated that these proteins are required for the proper duplication and segregation of the centrosome (major microtubule-organizing center; MTOC) in these cells. The full-length human cDNA, which they isolated from a T-cell lymphoblastic leukemia cDNA library, encodes a deduced 72-amino acid protein with 4 potential EF-hand calcium-binding domains. The protein shares 70% sequence identity with its algal counterpart.