Semenogelin-1 (SEMG1)

Semenogelin-1 (SEMG1) is a major secreted protein in human seminal plasma, encoded by the SEMG1 gene on chromosome 20[1][3]. It is the predominant structural component responsible for forming a gel matrix that encases ejaculated spermatozoa, thus ensuring initial semen coagulation after ejaculation[1][2][3][5]. The subsequent liquefaction, required for sperm motility, is mediated by prostate-specific antigen (PSA), which cleaves SEMG1 into bioactive peptides, some of which inhibit sperm motility or follicle-stimulating hormone secretion, and others show antimicrobial activity[3][6]. Major functions include regulation of sperm motility and capacitation, and provision of antimicrobial protection to sperm[3][4][5][6]. SEMG1 is classified as a cancer/testis antigen (CT103), meaning it is normally restricted to reproductive tissues but can be aberrantly expressed in certain cancers, though its precise pathological roles in malignancy are underexplored[5]. No approved drugs are known to target SEMG1 directly, and it is not considered a therapeutic target (receptor, enzyme, transporter, etc.), but its role in reproduction and immunogenicity in some cancers make it a potential biomarker candidate in those contexts[3][5][7].

Other names

Semenogelin IAlpha-inhibin-92Alpha-inhibin-31Seminal basic proteinSEMGSGICT103Cancer/testis antigen 103Semen coagulating proteindJ172H20.2SgI-29