Abstract
Plant cytokinesis is accomplished with the formation of phragmoplast, which is formed between two daughter chromatins during anaphase. The development of phragmoplast is regulated by the MAP kinase cascade. Although the MAP65, one of microtubule binding proteins, has been shown to be phosphorylated by MAPK, most of targets are unidentified. We applied the phosphoprotein purification with immobilized metal ion affinity chromatography and two-dimensional difference in gel electrophoresis for the identification of the phosphorylated targets of MAP kinase cascade in Arabidopsis. We identified PATL2 as one of the targets of MAP kinase and found that recombinant PATL2 protein was phosphorylated by MAPK in vitro. Further analysis identified one serine residue of PATL2 located in SEC14 domain was phosphorylated. Since PATL2 is a member of SEC14 family which were speculated to be involved in membrane metabolism and transport, MAPK cascade might regulate membrane trafficking concomitant with expansion of phragmoplast
