Polypeptide N-acetylgalactosaminyltransferase like 5 (GALNTL5)

Polypeptide N-acetylgalactosaminyltransferase like 5 (GALNTL5) is a member of the polypeptide N-acetylgalactosamine-transferase family, possessing conserved catalytic domains found in glycosyltransferases but lacking a functional lectin domain and verified enzymatic activity in vitro. This protein is almost exclusively expressed in the testis and is essential for spermatid maturation and normal sperm motility, likely participating in processes such as protein loading into acrosomes and assembly of the ubiquitin-proteasome system at the sperm neck region. Genetic mutations leading to loss or dysfunction of GALNTL5 are associated with male infertility, especially due to asthenozoospermia (immotile sperm syndrome). Despite being an “enzyme-like” protein, direct transferase activity for GALNTL5 has not been demonstrated in vitro, leading it to be considered an inactive or atypical member of its enzyme family. There are currently no clinically established drug interactions, mechanisms of action, or established use as a biomarker or therapeutic target.

Other names

GALNT15GalNAc-T5LPolypeptide GalNAc transferase 15Polypeptide GalNAc transferase-like 5UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase-like 5Inactive polypeptide N-acetylgalactosaminyltransferase-like protein 5UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 15Protein-UDP acetylgalactosaminyltransferase 15Pp-GaNTase 15GalNAc-T15GALNACT19Testis tissue sperm-binding protein Li 61n