Transmembrane Protease, Serine 13 (TMPRSS13)

MSPL encodes a deduced 581-amino acid protein, and MSPS encodes a deduced 537-amino acid protein. Both isoforms contain 4 potential N-glycosylation sites. Except for the C-terminal ends, the 2 proteins have an identical serine protease domain exhibiting 42%, 39%, and 43% identity to those of human plasma kallikrein , hepsin, and transmembrane protease serine-2, respectively.

MSPL contains a transmembrane domain but MSPS does not. The noncatalytic regions of both isoforms contain domains that may be involved in protein-protein interactions, including tandem repeat motifs corresponding to the phosphorylation sites of cyclin-dependent kinase Cdc2 and protein kinase C, and a low density lipoprotein receptor-like domain.