Calmodulin, Calcium/Calmodulin-Dependent Kinases-1 and 2 Regulate Expression of the Heat Shock Proteins for Heat Shock Tolerance and Pheromone Signaling Genes for Sexual Development in Neurospora crassa .

UNLABELLED: Calmodulin (CaM) is a primary Ca2+ sensor that binds and activates numerous target proteins and regulates several cellular processes in eukaryotes. CaM is essential in Neurospora crassa ; therefore, we generated a CaM mutant using repeat-induced point (RIP) mutation and investigated the cmd RIP mutant phenotypes. We also studied knockout mutants of four Ca2+ /CaM kinases ( camk-1 , 2 , 3 , and 4 ) for their role during stress conditions and sexual development. The cmd RIP , ∆ camk-1 , and ∆ camk-2 mutants showed reduced survival and growth rates under heat stress, oxidative stress, pH, and ER stress conditions. In addition, under the heat stress conditions, expression of the heat shock protein genes hsp70 and hsp80 was reduced in the cmd RIP , ∆ camk-1 , and ∆ camk-2 mutants. The cmd RIP mutant was also defective in cell fusion, its vegetative hyphae could not support the fertilized wild type perithecia graft, and female sterile. Furthermore, the expression of pheromone signaling genes pre-1 , pre-2 , ccg-4 , mfa-1 , and fmf-1 was reduced in the cmd RIP , ∆ camk-1 , and ∆ camk-2 mutants. Therefore, CaM, Ca2+ /CaMK-1 and 2 are involved in the tolerance to heat stress conditions and sexual development by regulating the heat shock and pheromone response pathways, respectively, in N. crassa.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12088-023-01091-8.