TMPRSS4 protein structure and amino acid sequence alignment with its orthologs. A) A schematic representation of TMPRSS4 protein domain structure. At the N-terminal the protein has a transmembrane domain, a LDL-receptor A domain, and a scavenger receptor domain. The C-terminal encodes for the trypsin-like serine protease domain which contains the catalytic triad amino acids (histidine, aspartic acid, serine). The T332 residue (indicated with a red star) is also found within this domain. B) Multiple alignments (using ClustalW) demonstrate that T332 residue (highlighted in red) is highly conserved across a representative set of species-specific TMPRSS4 orthologs.