Histidine to aspartate phosphotransferase activity of nm23 proteins: phosphorylation of aldolase C on Asp-319.
nm23 genes have been implicated in the suppression of tumour metastasis and cell motility; however, the biochemical mechanisms for these suppressions are not known. We have previously described the transfer of phosphate from the catalytic histidine residues of nm23 proteins to an aspartic or a glutamic residue on one or more 43 kDa proteins in detergent extracts of bovine brain membranes. To gain a better understanding of this transferase activity, we partly purified this 43 kDa protein and identified aldolases A and C as the major 43 kDa proteins present in the preparation. Aldolase was purified from brain cytosol; its phosphorylation by rat liver nm23 proteins and by recombinant human nm23-H1 was examined. The site of phosphorylation was identified as Asp-319 on aldolase C. The equivalent residue on aldolase A, a glutamic residue, was not phosphorylated. Aldolase C was rapidly phosphorylated by wild-type nm23-H1 but was not phosphorylated, or was phosphorylated very slowly, by either nm23-H1(P96S) or nm23-H1(S120G), mutants of nm23-H1 that do not suppress cell motility. This is the first identification of a protein that is phosphorylated on an aspartic residue by nm23 proteins. The sequence around Asp-319 of aldolase C has some similarities to those around the histidine residues on ATP-citrate lyase and succinic thiokinase that are phosphorylated by nm23 proteins.
Wagner
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Laboratory of Biochemistry, National Cancer Institute, Bethesda, MD 20892-4255, USA. wagnerp@dc37a.nci.nih.gov
Vu
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D000595:Amino Acid Sequence; D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism*; D001921:Brain / Q000201:enzymology; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism*; D006639:Histidine / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism*; D009132:Muscles / Q000201:enzymology; D054778:NM23 Nucleoside Diphosphate Kinases; D009701:Nucleoside-Diphosphate Kinase / Q000378:metabolism; D010766:Phosphorylation; D010770:Phosphotransferases / Q000737:chemistry / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D017386:Sequence Homology, Amino Acid; D020358:Sodium Cholate / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism*
D054778:NM23 Nucleoside Diphosphate Kinases; D014157:Transcription Factors; D001224:Aspartic Acid; D006639:Histidine; D010770:Phosphotransferases; C517938:NME1 protein, human; D009701:Nucleoside-Diphosphate Kinase; D020559:Monomeric GTP-Binding Proteins; D005634:Fructose-Bisphosphate Aldolase; D020358:Sodium Cholate