Molecular cloning and expression of a variant form of hippostasin/KLK11 in prostate.
BACKGROUND
Hippostasin is a kallikrein-like serine protease, which has two alternatively spliced isoforms, brain-type and prostate-type. We previously reported alternative expression of hippostasin in prostate cancer cell lines.


METHODS
We studied the expression of a variant-form hippostasin (isoform 3) mRNA by RT-PCR. Localization of the isoform 3 protein was examined by immunohistochemistry. The enzymatic activity of the recombinant protein was measured with synthetic substrates.


RESULTS
A novel isoform of hippostasin contains 25 additional amino acids in the catalytic triad of brain-type hippostasin. Its mRNA was expressed in normal prostate tissue, BPH, and prostate cancer cell lines. The protein was localized in the prostate secretory epithelium. The enzyme activity was similar to that of brain-type hippostasin, which has kallikrein-like activity.


CONCLUSIONS
In this study, we have identified a third isoform of hippostasin, which was designated variant-form (isoform 3). Hippostasin isoform 3 may play a role in the prostate, including reproductive and/or tumorigenic functions.
Nakamura
Terukazu
T
Department of Urology, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, Japan.
Mitsui
Shinichi
S
Okui
Akira
A
Miki
Tsuneharu
T
Yamaguchi
Nozomi
N
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D008297:Male; D008969:Molecular Sequence Data; D011467:Prostate / Q000201:enzymology*; D011471:Prostatic Neoplasms; D012333:RNA, Messenger / Q000032:analysis; D012697:Serine Endopeptidases / Q000235:genetics* / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; C114880:trypsin-like serine protease; D012697:Serine Endopeptidases