MORN motifs in plant PIPKs are involved in the regulation of subcellular localization and phospholipid binding  

作　　者：Hui Ma Ying Lou Wen Hui Lin Hong Wei Xue 

机构地区：[1]National Key Laboratory of Plant Molecular Genetics,Institute of Plant Physiology and Ecology,Shanghai Institutes for Biological Science(SIBS),Chinese Academy of Sciences,and Parmer Group of Max-Planck-Institute of Molecular Plant Physiology(MPI-MP)on"Plant Molecular Physiology and Signal Transduction",300 Fenglin Road,200032 Shanghai,China

出　　处：《Cell Research》2006年第5期466-478,共13页细胞研究(英文版)

摘　　要：Multiple repeats of membrane occupation and recognition nexus (MORN) motifs were detected in plant phosphatidylinositl monophosphate kinase (PIPK), a key enzyme in PI-signaling pathway. Structural analysis indicates that all the MORN motifs (with varied numbers at ranges of 7-9), which shared high homologies to those of animal ones, were located at N-terminus and sequentially arranged, except those of OsPIPK1 and AtPIPK7, in which the last MORN motif was separated others by an -100 amino-acid "island" region, revealing the presence of two kinds of MORN arrangements in plant PIPKs. Through employing a yeast-based SMET (sequence of membrane-targeting) system, the MORN motifs were shown being able to target the fusion proteins to cell plasma membrane, which were further confirmed by expression of fused MORN-GFP proteins. Further detailed analysis via deletion studies indicated the MORN motifs in OsPIPK 1, together with the 104 amino-acid "island" region are involved in the regulation of differential subcellular localization, i.e. plasma membrane or nucleus, of the fused proteins. Fat Western blot analysis of the recombinant MORN polypeptide, expressed in Escherichia coli, showed that MORN motifs could strongly bind to PA and relatively slightly to PI4P and PI(4,5)P2. These results provide informative hints on mechanisms of subcellular localization, as well as regulation of substrate binding, of plant PIPKs.

关 键 词：membrane targeting PIPK MORN motif subcellular localization 

分 类 号：Q942[生物学—植物学]