ACTIVATION OF NEUTRAL TREHALASE BY GLUCOSE AND NITROGEN-SOURCE IN SCHIZOSACCHAROMYCES-POMBE STRAINS DEFICIENT IN CAMP-DEPENDENT PROTEIN-KINASE ACTIVITY

Schizosaccharomyces pombe cells carrying a disruption in the PKA1 gene , that encodes the catalytic subunit of cAMP-dependent protein kinase (PKA), lacked the glucose- and nitrogen-source-induced activation of t rehalase at stationary-phase but rised trehalase activity in response to these compounds during the exponential phase of growth, Treatment b y phosphatase of either glucose- or nitrogen-source-activated trehalas e resulted in trehalase deactivation suggesting that phosphorylation o f the enzyme protein occurs during activation, These data indicate tha t in growing cells of this yeast the mechanism responsible for the act ivation of trehalase can be independent of interactions with free cata lytic subunits of PKA and related to a signaling pathway involving a t ype of protein kinase different from PKA.