A Calcium-Dependent Protein Kinase Interactswith and Activates A Calcium Channel toRequlate Pollen Tube Growth

作     者：Liming Zhou[a][b] Wenzhi Lan[a][c] Yuanqing Jiang[a] Wei Fang[b] Sheng Luan[a] 

作者机构：[a] Department of Plant and Microbial Biology University of California Berkeley CA 94720 USA [b] College of Life Sciences Hebei United University Tangshan Hebei 063000 China [c] NJU–NJFU Joint Institute for Plant Molecular Biology School of Life Sciences Nanjing University Nanjing 210093 China 

出 版 物：《Molecular Plant》 (分子植物（英文版）)

年 卷 期：2014年第7卷第2期

页      面：369-376页

核心收录：

学科分类：0710[理学-生物学] 071001[理学-植物学] 07[理学] 

基　　金：supported by a grant from the National Science Foundation (to S.L.) Tangshan Plan of Science and Technology Research & Development 

主　　题：pollen tubes calcium-dependent protein kinase cyclic nucleotide-gated channel Ca2+ oscillations 

摘      要：ABSTRACT Calcium, as a ubiquitous second messenger, plays essential roles in tip-growing cells, such as animal neu-rons, plant pollen tubes, and root hairs. However, little is known concerning the regulatory mechanisms that code anddecode Ca2＋ signals in plants. The evidence presented here indicates that a calcium-dependent protein kinase, CPK32,controls polar growth of pollen tubes. Overexpression of CPK32 disrupted the polar growth along with excessive Ca2＋accumulation in the tip. A search of downstream effector molecules for CPK32 led to identification of a cyclic nucleotide-gated channel, CNGC18, as an interacting partner for CPK32. Co-expression of CPK32 and CNGC18 resulted in activationof CNGC18 in Xenopus oocytes where expression of CNGC18 alone did not exhibit significant calcium channel *** of CNGC18 produced a growth arrest phenotype coupled with accumulation of calcium in the tip, simi-lar to that induced by CPK32 overexpression. Co-expression of CPK32 and CNGC18 had a synergistic effect leading tomore severe depolarization of pollen tube growth. These results provide a potential feed-forward mechanism in whichcalcium-activated CPK32 activates CNGC18, further promoting calcium entry during the elevation phase of Ca2＋ oscilla-tions in the polar growth of pollen tubes.