Nucieocytoplasmic Shuttling of Geminivirus C4 Protein Mediated by Phosphorylation and Myristoylation Is Critical for Viral Pathogenicity  

作　　者：Yuzhen Mei Yaqin Wang Tao Hu Xiuling Yang Rosa Lozano-Duran Garry Sunter Xueping Zhou 

机构地区：[1]State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China [2]State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China [3]Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China [4]Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, USA

出　　处：《Molecular Plant》2018年第12期1466-1481,共16页分子植物（英文版）

基　　金：grants from the National Natural Science Foundation of China (31720103914 and 31390422).

摘　　要：Many geminivirus C4 proteins induce severe developmental abnormalities in plants.We previously demon- strated that Tomato leaf curl Yunnan virus (TLCYnV)C4 induces plant developmental abnormalities at least partically by decreasing the accumulation of NbSKη,an ortholog of Arabidopsis BIN2 kinase involved in the brassinosteroid signaling pathway,in the nucleus through directing it to the plasma membrane.However, the molecular mechanism by which the membrane-associated C4 modifies the localization of NbSKη in the host cell remains unclear.Here,we show that TLCYnV C4 is a nucleocytoplasmic shuttle protein,and that C4 shuttling is accompanied by nuclear export of NbSKTI.TLCYnV C4 is phosphorylated by NbSKη in the nucleus,which promotes myristoylation of the viral protein.Myristoylation of phosphorylated C4 favors its interaction with exportin-α(XPO I);which in turn facilitates nuclear export of the C4/NbSKTI complex. Supporting this model,chemical inhibition of N-myristoyltransferases or exportin-α enhanced nuclear retention of C4,and mutations of the putative phosphorylation or myristoylation sites in C4 resulted in increased nuclear retention ofrC4 and thus decreased severity of C4-induced developmental abnormalities. The impact of C4 on development is also lessened when a nuclear localization signal or a nuclear export signal is added to its C-terminus,restricting it to a specific cellular niche and therefore impairing nucleocytoplasmic shuttling.Taken together,our results suggest that nucleocytoplasmic shuttling of TLCYnV C4,enabled by phosphorylation by NbSKη,myristoylation,and interaction with exportin-α is critical for its function as a pathogenicity factor.

关 键 词：GEMINIVIRUS C4 PHOSPHORYLATION MYRISTOYLATION PATHOGENICITY nucleocytoplasmic SHUTTLING 

分 类 号：Q[生物学]