Identification and Characterization of KLK14, a Novel Kallikrein Serine Protease Gene Located on Human Chromosome 19q13.4 and Expressed in Prostate amd Skeletal Muscle

The kallikreins are a subfamily of serine proteases encoded in human, mouse, and rat by highly conserved tightly clustered multigene families. Here we report the identification and characterization of KLK14, a novel kallikrein gene located within the human kallikrein locus at 19q13.4. KLK14 is approximately 5.4 kb in length spanning seven exons and, by Northern blot analysis, transcribes two alternative transcripts present only in prostate (1.5 kb) and skeletal muscle (1.9 kb). The protein product, K14, predicted to be a 251-amino-acid secreted serine protease with trypsin-like substrate specificity, is translated in vitro with a molecular mass of ;31 kDa. In situ hybridization revealed that, in prostate, KLK14 is expressed by both benign and malignant glandular epithelial cells, thus exhibiting an expression pattern similar to that of two other prostatic kallikreins, KLK2 and KLK3, which encode K2 and prostate-specific antigen,respectively.