Molecular cloning of human phosphomevalonate kinase and identification of a consensus peroxisomal targeting sequence.
Two overlapping cDNAs which encode human liver phosphomevalonate kinase (PMKase) were isolated. The human PMKase cDNAs predict a 191-amino acid protein with a molecular weight of 21,862, consistent with previous reports for mammalian PMKase (Mr = 21,000-22,500). Further verification of the clones was obtained by expression of PMKase activity in bacteria using a composite 1024-base pair cDNA clone. Northern blot analysis of several human tissues revealed a doublet of transcripts at approximately 1 kilobase (kb) in heart, liver, skeletal muscle, kidney, and pancreas and lower but detectable transcript levels in brain, placenta, and lung. Analysis of transcripts from human lymphoblasts subcultured in lipid-depleted sera (LDS) and LDS supplemented with lovastatin indicated that PMKase gene expression is subject to regulation by sterol at the level of transcription. Southern blotting indicated that PMKase is a single copy gene covering less than 15 kb in the human genome. The human PMKase amino acid sequence contains a consensus peroxisomal targeting sequence (PTS-1), Ser-Arg-Leu, at the C terminus of the protein. This is the first report of a cholesterol biosynthetic protein which contains a consensus PTS-1, providing further evidence for the concept that early cholesterol and nonsterol isoprenoid biosynthesis may occur in the peroxisome.
Chambliss
K L
KL
Institute of Metabolic Disease, Baylor Research Institute and Baylor University Medical Center, Dallas, Texas 75226, USA.
Slaughter
C A
CA
Schreiner
R
R
Hoffmann
G F
GF
Gibson
K M
KM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D003001:Cloning, Molecular; D016384:Consensus Sequence; D017931:DNA Primers; D015342:DNA Probes; D005260:Female; D006801:Humans; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008214:Lymphocytes / Q000201:enzymology; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D010179:Pancreas / Q000201:enzymology; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D010920:Placenta / Q000201:enzymology; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D014158:Transcription, Genetic
D017931:DNA Primers; D015342:DNA Probes; D011994:Recombinant Proteins; D017856:Phosphotransferases (Phosphate Group Acceptor); C022371:phosphomevalonate kinase