Evidence for a modulation of neutral trehalase activity by Ca2+ and cAMP signaling pathways in Saccharomyces cerevisiae

Abstract

Saccharomyces cerevisiae neutral trehalase (encoded by NTH1) is regulated by cAMP-dependent protein kinase (PKA) and by an endogenous modulator protein. A yeast strain with knockouts of CMK1 and CMK2 genes (cmk1cmk2) and its isogenic control (CMK1CMK2) were used to investigate the role of CaM kinase II in the in vitro activation of neutral trehalase during growth on glucose. In the exponential growth phase, cmk1cmk2 cells exhibited basal trehalase activity and an activation ratio by PKA very similar to that found in CMK1CMK2 cells. At diauxie, even though both cells presented comparable basal trehalase activities, cmk1cmk2 cells showed reduced activation by PKA and lower total trehalase activity when compared to CMK1CMK2 cells. To determine if CaM kinase II regulates NTH1 expression or is involved in post-translational modulation of neutral trehalase activity, NTH1 promoter activity was evaluated using an NTH1-lacZ reporter gene. Similar ß-galactosidase activities were found for CMK1CMK2 and cmk1cmk2 cells, ruling out the role of CaM kinase II in NTH1 expression. Thus, CaM kinase II should act in concert with PKA on the activation of the cryptic form of neutral trehalase. A model for trehalase regulation by CaM kinase II is proposed whereby the target protein for Ca 2+ /CaM-dependent kinase II phosphorylation is not the neutral trehalase itself. The possible identity of this target protein with the recently identified trehalaseassociated protein YLR270Wp is discussed.

Screening and characterization of endophytic fungi of Panax ginseng Meyer for biocontrol activity against ginseng pathogens

“…B. cinerea tre1 mutants showed delayed spore germination due to the accumulation of trehalose and inability of trehalose mobilization (Döhlemann et al 2006). TRE1 activity in B. cinerea was dependent on cAMP signaling in accordance with the activation of TRE1, which was mediated by cAMP-dependent PKA (Souza et al, 2002).…”

In silico and in vivo analysis reveal a novel gene in Saccharomyces cerevisiae trehalose metabolism

“…The first property observed for the Ylr270p was its ability to bind to trehalase therefore, we renamed it as Trehalase Associated Protein, Tap [9]. Later, Liu et al .…”

Trehalose metabolism is important for heat stress tolerance and spore germination of Botrytis cinerea

“…However, addition of cAMP to these conidia resulted in significant mobilization of trehalose and accelerated germination. In Saccharomyces cerevisiae, trehalose breakdown requires activation of the neutral trehalase, mediated by cAMP-dependent protein kinase A and possibly Ca 2+ (Souza et al, 2002;d'Enfert 1997;de Almeida et al, 1997). The inability of adenylate-cyclasedeficient N. crassa mutants to mobilize trehalose during germination also indicates that cAMP signalling is required for activation of neutral trehalase (de Pinho et al, 2001).…”