Protein function and interaction

The protein encoded by SEMG1, semenogelin-1, is the predominant protein in semen ((Ulvsbäck et al., 1992 PMID: 1517240). In seminal plasma and in ejaculated spermatozoa, semenogelin-1 is associated with SPINLW1, also known as eppin (Wang et al., 2005 PMID: 15590901). These two proteins form a complex with lactotransferrin and clusterin. This complex may provide a surface network with microbicidal properties that protects spermatozoa and may regulate sperm motility (Wang et al., 2007 PMID: 17567961). The antibacterial activity is derived from peptides generated by fragmentation of the semenogelins (Edström et al., 2008 PMID: 18714013). PSA (prostate-specific antigen) is the main enzyme responsible for the processing of semenogelin-1 in human semen (Robert et al., 1997 PMID: 9092810). Semenogelin-1 was also shown to inhibit sperm motility by directly binding to the sperm surface (Yoshida et al., 2008 PMID: 18203809). Semenogelins I and II may regulate the activity of the prostate-specific antigen (Jonsson et al. 2005 PMID: 15563730).