Biosynthesis of glycoproteins in the pathogenic fungus Candida albicans: activation of dolichol phosphate mannose synthase by cAMP-mediated protein phosphorylation.
Following incubation with ATP and a cAMP-dependent protein kinase under optimal conditions of lipid acceptor, phospholipid and metal ion requirements, the transfer activity of partially purified dolichol phosphate mannose synthase (DPMS) increased about 60% and this activation correlated with a 50% increase in V(max) with no alteration in the apparent K(m) for GDP-Manose. Phosphorylation with [gamma-(32)P]ATP resulted in the labeling of several polypeptides, one of which exhibited the molecular weight of the enzyme (30 kDa) and was also recognized using a specific anti-DPMS monoclonal antibody. This and the fact that the phosphate label could be removed by an alkaline phosphatase indicate that Candida DPMS may be regulated by phosphorylation-dephosphorylation, a mechanism that has been proposed for the enzyme in other organisms.
Arroyo-Flores
Blanca L
BL
Instituto de Investigación en Biología Experimental, Facultad de Química, Universidad de Guanajuato, Mexico.
Calvo-Méndez
Carlos
C
Flores-Carreón
Arturo
A
López-Romero
Everardo
E
D002176:Candida albicans / Q000201:enzymology* / Q000254:growth & development / Q000472:pathogenicity; D003470:Culture Media; D000242:Cyclic AMP / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D006023:Glycoproteins / Q000096:biosynthesis*; D006031:Glycosylation; D006801:Humans; D007700:Kinetics; D008364:Mannosyltransferases / Q000378:metabolism*; D010766:Phosphorylation
D003470:Culture Media; D006023:Glycoproteins; D000242:Cyclic AMP; D008364:Mannosyltransferases; C022755:dolichyl-phosphate beta-D-mannosyltransferase