Androglobin (ADGB)

Androglobin (ADGB) is a multi-domain chimeric protein that contains an N-terminal calpain-like cysteine protease domain, a central circularly permuted (non-canonical) globin domain, an IQ motif putatively for calmodulin-binding, and a large C-terminal region of unknown function[1][2][3]. It is the fifth mammalian globin discovered and is predominantly expressed in the testis, with essential roles in spermatogenesis and male fertility—ADGB knockout mice are infertile, show defective sperm maturation, abnormal sperm morphology, and disorganization of flagellar microtubules and mitochondria[2][3]. Biochemically, the globin domain of ADGB can bind heme and may participate in unique nitrite reduction activity, as well as bind nitric oxide in an unusual penta-coordinated fashion, indicating specialized oxygen or gas signaling roles in the testis[1]. Mechanistically, ADGB interacts specifically with septin 10 (SEPT10), influencing annulus structure in sperm and is thought to mediate proteolysis of certain cytoskeletal proteins in a calmodulin-dependent manner, affecting sperm head shaping and flagellum growth[2][3]. There are currently no known drug interactions or therapeutic targeting programs for ADGB. Decreased testicular ADGB expression has been observed in infertile males, indicating potential as a biomarker for sperm maturation defects[3].

Other names

C6orf103FLJ23121dJ408K24.1CAPN16calpain-7-like protein