title: Identification of human male germ cell-associated kinase, a kinase transcriptionally activated by androgen in prostate cancer cells.
abstract: Androgen is involved in both normal development and malignant transformation of prostate cells. The signal transduction pathways associated with these processes are not well understood. Using a novel kinase display approach, we have identified a protein kinase, human male germ cell-associated kinase (hMAK), which is transcriptionally induced by the androgenic hormone 5alpha-dihydrotestosterone (DHT). The kinetics of induction is rapid and dose-dependent, and the induction is not blocked by cycloheximide treatment. Real time reverse transcription-PCR studies demonstrated a 9-fold induction of hMAK by 10 nm DHT at 24 h post-stimulation. The expression levels of hMAK in prostate cancer cell lines are in general higher than those of normal prostate epithelial cells. A reverse transcription-PCR product encompassing the entire hMAK open reading frame was isolated. The results from sequencing analysis showed that the hMAK protein is 623 amino acids in length and contains a kinase catalytic domain at its N terminus, followed by a proline/glutamine-rich domain. The catalytic domain of this kinase contains sequence motifs related to both the cyclin-dependent kinase and the mitogen-activated protein kinase families. When expressed in COS1 cells, hMAK is kinase-active as demonstrated by autophosphorylation and phosphorylation of exogenous substrate and is localized in the nucleus. A 3.7-kilobase pair promoter of the hMAK locus was isolated from a human genomic DNA bacterial artificial chromosome clone and was shown to be activated by DHT. This activation can be blocked by an anti-androgen drug bicalutamide (Casodex), implicating the involvement of androgen receptor in this process. Taken together, these data suggest that hMAK is a protein kinase targeted by androgen that may participate in androgen-mediated signaling in prostate cancer cells.
authors.affiliation: Department of Biological Chemistry, School of Medicine, University of California, Davis, California 95616, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Xia
authors.forename: Dan
authors.initials: D
authors.lastname: Robinson
authors.forename: Ai-Hong
authors.initials: AH
authors.lastname: Ma
authors.forename: Hua-Chien
authors.initials: HC
authors.lastname: Chen
authors.forename: Frederick
authors.initials: F
authors.lastname: Wu
authors.forename: Yun
authors.initials: Y
authors.lastname: Qiu
authors.forename: Hsing-Jien
authors.initials: HJ
authors.lastname: Kung
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020134:Catalytic Domain; D003001:Cloning, Molecular; D018076:DNA, Complementary; D013196:Dihydrotestosterone / Q000494:pharmacology*; D004789:Enzyme Activation; D004790:Enzyme Induction; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010766:Phosphorylation; D010802:Phylogeny; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000473:pathology; D011494:Protein Kinases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000201:enzymology; D014407:Tumor Cells, Cultured
chemical_list: D018076:DNA, Complementary; D013196:Dihydrotestosterone; D011494:Protein Kinases; C466802:male germ cell-associated kinase, human