Stimulation of beta(1----3)glucan synthetase of various fungi by nucleoside triphosphates: generalized regulatory mechanism for cell wall biosynthesis

Abstract

Particulate fractions from the taxonomically diverse fungi Achlya ambisexualis, Hansenula anomala, Neurospora crassa, Cryptococcus laurentii, Schizophyllum commune and Wangiella dematitis catalyzed the time-dependent incorporation of glucose from UDP-[14C]glucose into a water-insoluble material. The reaction was stimulated by bovine serum albumin. The product was characterized as .beta.(1 .fwdarw. 3)glucan on the basis of its resistance to .alpha.- and .beta.-amylase and susceptibility to .beta.(1 .fwdarw. 3)glucanase. With the exception of the preparation from A. ambisexualis, all others were stimulated by nucleoside triphosphate and their analogs. The best activators were GTP and guanosine 5''-(.gamma.-thio)triphosphate. The stimulation by nucleotides, previously found with the glucan synthetase of Saccharomyces cerevisiae, is a regulatory mechanism that was well conserved during fungal evolution, presumably because of its importance in controlling cell wall biosynthesis and cell growth.