CABYR (Calcium-Binding Tyrosine phosphorylation-Regulated Protein, Calcium-Binding Protein 86, Cancer/Testis Antigen 88, CT88, Fibrousheathin II, Fibrousheathin-2, FSP-2, Testis-specific Calcium-Binding Protein CBP86, CBP86, FSP2)

Spermatozoa gain fertilization capacitation and hyperactivation after residing in the uterus or oviduct. Calcium, cAMP and protein tyrosine phosphorylation are necessary for the molecular mechanisms that allow for this transformation. CABYR (Calcium-binding tyrosine phosphorylation-regulated protein), also known as Fibrousheathin-2 or Cancer/testis antigen 88, is a 493 amino acid protein that is expressed in sperm flagella and exhibits increased tyrosine phosphorylation during capacitation. There are six named isoforms of CABYR that are produced as a result of alternative slicing events. Specifically,...