Phosphoinositide-specific phospholipase C forms a complex with 14-3-3 proteins and is involved in expression of UV resistance in fission yeast

Abstract

The fission yeast plc1+ gene encodes phosphoinositide-specific phospholipase C. The two- hybrid interaction assay with plexA-plc1+ as a bait revealed that Plc1p interacted with the 14-3-3 proteins Rad24p and Rad25p. Formation of a complex containing Plc1p and Rad24p in vivo was confirmed by an immunological method. As predicted from the fact that rad24 null mutant cells are hypersensitive to UV irradiation, plc1 null mutant cells were almost as sensitive to UV irradiation as rad24 null mutant cells. In addition, deletion of rad24 in the plc1 null mutant cells did not enhance the UV sensitivity, indicating that plc1+ and rad24+ belong to the same epistasis group with respect to UV sensitivity. Whereas Rad24p has been reported to be involved in the DNA damage checkpoint pathway, the delay to mitosis after UV irradiation was not defective either in rad24 null mutant cells or in plcl null mutant cells in our analysis. Thus, Plc1p is responsible for resistance to UV irradiation, but not for the DNA damage checkpoint pathway, in cooperation with 14-3-3 proteins.

Yeast 14‐3‐3 proteins

“…pombe Plc1p interacts physically with the 14-3-3 proteins Rad24 and Rad25, 1 although the 14-3-3s do not appear to regulate the activity of Plc1p. Contrary to other reports, Andoh et al 1 could not find an effect of Rad24p on the DNA damage checkpoint. This might be due to the difference in the source of radiation used or by the pleiotropic phenotype of a rad24 mutant.…”

“…Both rad24 and plc1 mutants are hypersensitive to UV radiation. 1 Phosphoinositidespecific phospholipase C catalyses the hydrolysis of phosphatidylinositol 4,5-bisphosphate and produces the second messengers inositol 1,4,5-triphosphate (IP 3 ) and diacylglycerol (DAG), which cause a rise in intracellular Ca 2+ and activation of protein kinase C, respectively. PLC isoforms are present in many organisms and are regulated by a wide variety of extracellular signals and signalling pathways (for a review, see Katan.…”

Phosphatidylinositol-4-phosphate 5-Kinase Regulates Fission Yeast Cell Integrity through a Phospholipase C-mediated Protein Kinase C-independent Pathway

“…Another agent tested was ZnSO 4 . Various phenotypes of the ⌬plc1 strain have been reported (16,32); however, we found that most of these phenotypes were not very evident when the auxotrophic markers were eliminated. Instead, we found that the ⌬plc1 strain, unlike the other mutants tested, was hypersensitive to ZnSO 4 .…”

The Candida albicans 14‐3‐3 gene, BMH1, is essential for growth

“…However, strains deleted in either BMH1 or BMH2 show increased sensitivity to rapamycin compared to parent strains (Bertram et al, 1998). Strains deleted in both 14-3-3 genes are normally inviable (Andoh et al, 1998;Gelperin et al, 1995;van Heusden et al, 1995). However, in the S. cerevisiae strain background S1278b, a bmh1/bmh2 double knockout is viable but exhibits sensitivity to environmental stresses (Roberts et al, 1997).…”

“…pombe, 14-3-3 proteins play a role in radiation resistance and cell cycle control (Ford et al, 1994). Radiation resistance is accomplished after association with phospholipase C (Plc) but Plcp is not involved in checkpoint control (Andoh et al, 1998). In certain conditions, e.g.…”