Fig. 6

Mechanistic model of the cAMP and calcium signalling pathway in cellulase overexpression responding to Mn²⁺/DMF stimulation in T. reesei under cellulase-inducing conditions. Mn²⁺/DMF stimulation induces intracellular cAMP accumulation in an adenylate cyclase (ACY1)-dependent manner. An increase in cAMP levels induces a cytosolic Ca²⁺ burst that stimulates the Ca²⁺ signal transduction pathway to regulate cellulase expression in T. reesei under cellulase-inducing conditions. PLC is vital for cellulase overexpression in response to stimulation by both Mn²⁺ and DMF. cAMP induces Ca²⁺ bursts via PLC-E. The solid arrows indicate data supported by our own experiments, and the dashed arrows indicate other unknown regulation pathways