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Human cathepsin W, a putative cysteine protease predominantly expressed in CD8 + T‐lymphocytes
Author(s) -
Linnevers C,
Smeekens S.P,
Brömme D
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00118-x
Subject(s) - cathepsin h , cathepsin o , peptide sequence , biochemistry , microbiology and biotechnology , proteases , cathepsin c , cathepsin e , cathepsin , biology , cathepsin l1 , cysteine , cathepsin l , amino acid , cathepsin b , enzyme , gene
A 750‐bp fragment of a novel human cysteine protease has been identified from the dbEST databank. PCR cloning and DNA sequencing yielded a 1.38‐kb full‐length cDNA which encodes a polypeptide of 376 amino acids. The protein consists of a putative 21‐residue signal peptide, a 106‐residue propeptide and a 252‐residue mature protein. The deduced amino acid sequence contains the highly conserved residues of the catalytic triad of papain‐like cysteine proteases: cysteine, histidine, and asparagine. Furthermore, the protein sequence possesses two potential N ‐glycosylation sites: one in the propeptide and one in the mature protein. Comparison of the amino acid sequence of human cathepsin W with other human thiol‐dependent cathepsins revealed a relatively low degree of similarity (21–31%). In contrast to cathepsins L, S, K, B, H and O, cathepsin W contains a 21‐amino acid peptide insertion between the putative active site histidine and asparagine residues and an 8‐amino acid C‐terminal extension. This unique sequence may indicate that cathepsin W belongs in a novel subgroup of papain‐like proteases distinct from that of cathepsin L‐ and B‐like proteases. Northern blot analysis indicates a specific expression of cathepsin W in lymphatic tissues. Further analysis revealed predominant levels of expression in T‐lymphocytes, and more specifically in CD8 + cells. The expression of the protease in cytotoxic T‐lymphocytes may suggest a specific function in the mechanism or regulation of T‐cell cytolytic activity.