Rhophilin-associated tail protein 1B (ROPN1B)

Rhophilin-associated tail protein 1B (ROPN1B) is a testis-enriched, cytoplasmic protein that functions as an adaptor, predominantly found in the fibrous sheath of spermatozoa, and binds to A-kinase anchoring proteins such as AKAP110 to participate in PKA-dependent signaling processes essential for sperm motility and capacitation[5][8]. ROPN1B has 96% sequence homology with its paralog ROPN1A and is widely expressed as a cancer-testis antigen in several tumor types, notably melanoma, breast cancer, and hematological malignancies[2]. Its expression in tumors, particularly melanoma (with 88.5% of patient samples positive), is linked to poor prognosis and metastasis, possibly through RhoA signaling pathway activation[2]. ROPN1B’s role as a tumor antigen and its immunogenicity in cancer patients make it a promising subject for immunotherapy research, though no approved drugs currently target this molecule, and fertility concerns must be managed if considered for clinical targeting[2][5][8][1].

Other names

Ropporin-1BRhophilin-associated protein 1Bropporin-1BAKAP-binding sperm protein ropporinropporintestis tissue sperm-binding protein Li 83P