Is PLDδ a target for NO-mediated S-nitrosilation?

* AYELEN M. DISTÉFANO, MATIAS VALIÑAS, LORENZO LAMATTINA, CARLOS GARCÍA-MATA, ARJEN TEN HAVE AND ANA M. LAXALT.

Potrero de los Funes

Congreso; SAIB; 2011

Previously, we demonstrated that phospholipase Dδ (PLDδ), one of the 12 Arabidopsis PLDs, is downstream of nitric oxide (NO) signalling during stomatal closure. How NO activates PLDδ is still unknown. Since NO is a lipophilic compound, membrane proteins are theoretically more exposed to its chemistry. NO could directly act on proteins by nitrosylation of cysteins (S-nitrosylation), a reversible posttranslational modification. So far, there are no reports of S-nitrosylation of PLDs in either animals or plants. The aim of this study is to analyze whether PLDδ could be a target for S-nitrosylation. In order to determine whether any PLD from plants have the S-nitrosylation motif we did a PHI-Blast analysis. Many PLDs, including PLDδ, have the motif. A conserved domain database search identifies the start of the first PLD catalytic domain at the same position of the S-NO motif. In order to analyze whether PLDδ is S-nitrosylated, we transiently over express PLDδ with c-Myc tag in tobacco leaves. We observed the presence of AtPLDδ transcript by RT-PCR, measured in vitro increase PLD activity, however we could not detect the PLDδ-c-Myc protein. Interestingly, under well-water conditions these plants showed differences (tenses que diferencias? Mas conductancia? Menos conductancia?) in stomatal conductance respect to control ones. Under water deprivation they showed a wilting phenotype. These results support the role of PLDδ in water status balance. Unfortunately data about S-nitrosylation is still lacking. We are currently expressing PLDδ en bacteria in order to determined the S-nitrosylation of AtPLDδ