Identification of a 14-3-3 protein from Lentinus edodes that interacts with CAP (adenylyl cyclase-associated protein), and conservation of this interaction in fission yeast

We previously identified a gene encoding a CAP (adenylyl cyclase-associated protein) homologue from the edible Basidiomycete Lentinus edodes, To furth er discover the cellular functions of the CAP protein, we searched for CAP- interacting proteins using a yeast two-hybrid system. Among the candidates thus obtained, many clones encoded the C-terminal half of an L. edodes 14-3 -3 homologue (designated cip3), Southern blot analysis indicated that L, ed odes contains only one 14-3-3 gene. Overexpression of the L, edodes 14-3-3 protein in the fission yeast Schizosaccharomyces pombe rad24 null cells com plemented the loss of endogenous 14-3-3 protein functions in cell morpholog y and UV sensitivity, suggesting functional conservation of 14-3-3 proteins between L, edodes and S. pombe. The interaction between L. edodes CAP and 14-3-3 protein was restricted to the N-terminal domain of CAP and was confi rmed by in vitro co-precipitation, Results from both the two-hybrid system and in vivo co-precipitation experiments showed the conservation of this in teraction in S, pombe. The observation that a 14-3-3 protein interacts with the N-terminal portion of CAP but not with full-length CAP in L, edodes an d S, pombe suggests that the C-terminal region of CAP may have a negative e ffect on the interaction between CAP and 14-3-3 proteins, and 14-3-3 protei ns may play a role in regulation of CAP function.