title: Identification and characterization of hepsin/-TM, a non-transmembrane hepsin isoform.
abstract: Type II transmembrane serine proteases (TTSPs), including hepsin, are a new class of cell surface catalytic enzymes. In the present study, a non-transmembrane isoform of hepsin, named hepsin/-TM that originates from alternative splicing, was identified. Unlike the transmembrane hepsin isoform, this non-transmembrane isoform was distributed within the cytoplasm. Real-time PCR experiments revealed that while hepsin was expressed in all tested human tissues, hepsin/-TM was restricted in kidney, brain and lung tissues. Significantly, hepsin/-TM was not expressed in liver where hepsin was originally identified. However, hepsin/-TM was highly expressed in brain where hepsin was expressed at a relatively lower level. Moreover, these two isoforms showed different expression patterns in a number of colon adenocarcinoma cell lines. In addition, in contrast to hepsin, expression of hepsin/-TM in vivo does not exert any apparent inhibitory effect on mammalian cell growth.
authors.affiliation: Mammalian Cell Genetics, Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada H4P 2R2.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Zhenbao
authors.initials: Z
authors.lastname: Yu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Shi-Hsiang
authors.initials: SH
authors.lastname: Shen
mesh_terms: D003110:Colonic Neoplasms / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D007668:Kidney / Q000378:metabolism; D009928:Organ Specificity / Q000502:physiology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D020539:Sequence Analysis, Protein; D012697:Serine Endopeptidases / Q000235:genetics* / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D020033:Protein Isoforms; D012697:Serine Endopeptidases; C055645:hepsin