Activation of neutral trehalase by glucose and nitrogen source in Schizosaccharomyces pombe strains deficient in cAMP-dependent protein kinase activity

Abstract

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