Calcium-binding protein spermatid-associated 1 (CABS1)

Calcium-binding protein spermatid-associated 1 (CABS1) is a structurally disordered, calcium-binding protein primarily expressed in the testis and localized to developing spermatids, Leydig cells, Sertoli cells, primary spermatogonia, and spermatocytes in humans[1][3]. CABS1 is functionally important for the assembly and maintenance of the sperm flagellum, particularly the annulus and tail, impacting sperm motility[2][4]. Loss of CABS1 in mice leads to abnormal sperm tail structures and reduced male fertility, with increased frequencies of spermatozoa exhibiting bent tails due to disrupted expression of cytoskeletal proteins like Septin 4 and Krt1[2][4]. Beyond its established role in male germ cells, CABS1 protein and/or mRNA are also detected in other tissues (salivary glands, serum, gastrointestinal tract), where it may possess anti-inflammatory activity due to a unique heptapeptide sequence[1][3][4]. While no approved drugs directly target CABS1 and it is not considered a canonical therapeutic target, its function is critical in male reproduction, and it may have broader roles in other tissues[1][3][4][5].

Other names

Calcium-binding and spermatid-specific protein 1C4orf35NYD-SP26FLJ32897CLPHTestis development protein NYD-SP26casein-like phosphoproteincalcium-binding protein, sperm-specific 1calcium-binding protein, spermatid-specific 1