What does this mean? see below?

Question

The parallel induction of both PEPCase and PEPCase-K during the transition from C3 -CAM metabolism by salt stress provides support to the close linkage between the enzyme and the associated kinase The functioning of a signal transduction cascade in which phosphoinositide-specific phospholipase C catalyzes the production of the 2nd messenger inositol-1,4,5-trisphosphate for the stimulation of Ca2+ efflux from vacuole to cytosol. Upon increase of Ca2+, a Ca2+-dependent protein kinase stimulates translation of PEPCase-K mRNA or a putative activation factor. Most probable is cytosolic pH because of up-regulation of PEPCase-K and the associated phosphorylation of the up-regulation of PCase are highly stimulated by alkalinization of cytosol. In CAM plants, transcripts of the Ppck gene accumulate at night, causing accumulation of PCase-K and phosphorylation of PCase These contain further levels of regulation for the photosynthetic process. Salt-stress induces the rapid expression of Ppc genes

Answer 1

Ice plants such as Mesembyanthemum can be C3 or CAM depending on their growth conditions. Salinity induces CAM photosynthesis. CAM plants use PEP carboxylase to fix CO2 at night. The activity of PEP carboxylase is regulated by phosphorylation reactions mediated by another enzyme called PEP carboxylase kinase. How does night induce the functioning of PEP carboxylase kinase???

Phospholipase C ---> IP3 ---> Ca release from vacuole --->
increased cytoplasmic Ca ----> activation of a Ca-dependent protein kinase ----> increased PEP carboxylase kinase activity

The authors suggest that pH changes also play a role in this signal trsnducion pathway.

Answer 2

yes