Protein kinase A regulatory subunit isoforms regulate growth and differentiation in Mucor circinelloides: essential role of PKAR4

TUDISCA V, SIMPSON C, CASTELLI L, LUI J, HOYLE N, MORENO S, ASHE M, PORTELA P.

JOURNAL OF CELL SCIENCE

COMPANY OF BIOLOGISTS LTD

Lugar: Cambridge; Año: 2012

0021-9533

A variety of stress conditions induce mRNA and proteins aggregation into mRNA silencing foci, but the signalling pathways mediating these responses are still elusive. Previously we demonstrate that PKA catalytic isoforms Tpk2 and Tpk3 localize with processing and stress bodies in Saccharomyces cerevisiae. Here, we show that Tpk2 and Tpk3 are associated with translation initiation factors in exponentially growing cells. Glucose starvation promotes the loss of interaction between Tpk and initiation factors followed by their accumulation into processing bodies. Analysis of mutants in the individual PKA isoform genes has revealed that the TPK3 or TPK2 deletion affects the capacity of the cells to form granules and arrest translation properly in response to glucose starvation or stationary phase. Additional we demonstrated that PKA controls Rpg1 and eIF4G1 protein abundance possibly controlling the cap-dependent translation. Taken together, our data suggest that the PKA pathway coordinates multiple stages in the fate of mRNAs with nutritional environment and growth status of the cell.