title: Rice small C2-domain proteins are phosphorylated by calcium-dependent protein kinase.
abstract: We previously reported that OsERG1 and OsERG3 encode rice small C2-domain proteins with different biochemical properties in Ca(2+)- and phospholipid-binding assays. Os-ERG1 exhibited Ca(2+)-dependent phospholipid binding, which was not observed with OsERG3. In the present study, we show that both OsERG1 and OsERG3 proteins exhibit oligomerization properties as determined by native polyacrylamide gel electrophoresis (PAGE) and glutaraldehyde cross-linking experiments. Furthermore, in vitro phosphorylation assays reveal the phosphorylation of OsERG1 and OsERG3 by a rice calcium-dependent protein kinase, OsCDPK5. Our mutation analysis on putative serine phosphorylation sites shows that the first serine (Ser) at position 41 of OsERG1 may be an essential residue for phosphorylation by OsCDPK5. Mutation of Ser41 to alanine (OsERG1S41A) and aspartate (OsERG1S41D) abolishes the ability of OsERG1 to bind phospholipids regardless of the presence or absence of Ca(2+) ions. In addition, unlike the OsERG1 wild-type form, the mutant OsERG1 (S41A)::smGFP construct lost the ability to translocate from the cytosol to the plasma membrane in response to calcium ions or fungal elicitor. These results indicate that Ser41 may be essential for the function of OsERG1.
authors: Division of Applied Life Sciences (Brain Korea 21 Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Korea.
authors: Chang Ho
authors: CH
authors: Kang
authors: Byeong Cheol
authors: BC
authors: Moon
authors: Hyeong Cheol
authors: HC
authors: Park
authors: Sung Cheol
authors: SC
authors: Koo
authors: Yong Hun
authors: YH
authors: Chi
authors: Yong Hwa
authors: YH
authors: Cheong
authors: Byung-Dae
authors: BD
authors: Yoon
authors: Sang Yeol
authors: SY
authors: Lee
authors: Cha Young
authors: CY
authors: Kim
mesh_terms: D000409:Alanine / Q000235:genetics; D000595:Amino Acid Sequence; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000201:enzymology / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D012694:Serine / Q000235:genetics; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D000409:Alanine; D002118:Calcium; D010743:Phospholipids; D010940:Plant Proteins; D011494:Protein Kinases; D012694:Serine; C454865:calcium-dependent protein kinase, rice; D017871:Calcium-Calmodulin-Dependent Protein Kinases