Recombinant Mouse Spinesin Protein, CF

Spinesin, encoded by the TMPRSS5 gene, is a new member of type II transmembrane serine proteases (TTSPs) (1). Mouse Spinesin contains the following structural domains: a short N-terminal cytoplasmic tail, a transmembrane domain, a stem region and a serine protease domain (2). The domain structure of Spinesin is common to other TTSPs, many of which have additional domains. The stem region of Spinesin contains a scavenger receptor-like domain. There could be 4 types of transcripts due to alternative splicing (3). Type 4 predicts 10 extra amino acids at the N-terminus as compared to type 3. The ectodomain corresponding to type 3 (residues 61‑445) or  type 4 (residues 71‑455) was expressed and purified as a single chain pro-enzyme. By SDS‑PAGE, the pro‑enzyme migrates as multiple forms, possibly due to differential glycosylation. The pro‑enzyme can be activated by trypsin treatment. The resulting enzyme is active and its activity is measured as described above. The activated enzyme is a disulfide bond‑linked dimer.