Light-activated adenyl cyclase from Trichoderma viride

Abstract

The effect of light on adenyl cyclase (E.C. 4.6.1.1) and 3':5'-cyclic-AMP-phosphodiesterase (E.C. 3.1.4.17) activity of Trichoderma viride was investigated. Adenyl cyclase proved to be a membrane-associated enzyme, requiring Mn2+ and was activated by light. In contrast, 3':5'-cyclic-AMP-phosphodiesterase showed no light-stimulated activity. The activity of 3':5'-cyclic-AMP-phosphodiesterase was present mainly in the cytosol and was stimulated by Mg2+.

Cross Talk between a Fungal Blue-Light Perception System and the Cyclic AMP Signaling Pathway

“…dB-cAMP does not restore photoconidiation in the blr mutants. Data available in the literature suggest that cAMP could be involved in blue light-induced conidiation in Trichoderma (13,14,24). In addition, we have previously shown that application of exogenous dB-cAMP to Trichoderma cultures growing on rich medium triggers conidiation even in the dark (5).…”

“…No phr-1 mRNA is detected in the dark, becoming detectable immediately after a blue-light pulse (4). Among the biochemical changes evoked by illumination in dark-grown colonies are shifts in membrane potential and ATP levels, a transient biphasic oscillation in intracellular cyclic AMP (cAMP) levels, activation of adenylyl cyclase, and phosphorylation of proteins (13,14,24). Exogenous cAMP promotes sporulation in the dark (30), whereas atropine, a compound known to inhibit adenylyl cyclase in Neurospora (37), prevents sporulation even after photoinduction (5).…”

Trichoderma: sensing the environment for survival and dispersal

“…Consistent with the expected effect on adenylate cyclase activity of a subunit belonging to subgroup III, transformants expressing gna3 in antisense showed reduced levels of cAMP. In T. viride, high levels of cAMP have been directly correlated with conidiation (Gresik et al, 1988;Kolarova et al, 1992). Nevertheless, transformants expressing a constitutively active allele of GNA3 showed a reduction in conidiation ).…”

“…Biochemical changes detectable after light induction of conidiation include an increase in the activity of adenylate cyclase, protein phosphorylation, and transient increments in the levels of cAMP, all associated with the activation of a signalling pathway modulated by cAMP (Gresik et al, 1988;Kolarova et al, 1992). Further, addition of an analogue of cAMP (dibutyryl cAMP) to a T. atroviride colony growing in the dark triggers conidiation, while atropine, an adenylate cyclase inhibitor, blocks light-induced conidiation (Berrocal-Tito et al, 2000).…”

Novel Approaches to Improve Cellulase Biosynthesis for Biofuel Production – Adjusting Signal Transduction Pathways in the Biotechnological Workhorse Trichoderma reesei

“…This differential effect of components of t h e c A M P p a t h w a y i n d e p e n d e n c e o f l i g h t highlights its importance and a connection of this pathway to light dependent processes has been shown previously: Interestingly, cAMP levels and regulatory targets of cAMP react to different light conditions. The operation of adenylate cyclase of T. reesei, which is a membrane bound enzyme, is stimulated by light (Kolarova et al, 1992). PKA activity of T. atroviride is increased in light and overexpression of the regulatory subunit of PKA results in a blocking of light response genes (Casas-Flores et al, 2006).…”