模拟苏氨酸104磷酸化的烟草花叶病毒运动蛋白突变体的功能失调

Dysfunctionality of a tobacco mosaic virus movement protein mutant mimicking threonine 104 phosphorylation.

作者信息

Karger E M, Frolova O Yu, Fedorova N V, Baratova L A, Ovchinnikova T V, Susi P, Makinen K, Ronnstrand L, Dorokhov Yu L, Atabekov J G

机构信息

Department of Virology and A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Vorobiovy Gory Moscow 119899, Russia.

M. M. Shemyakin and Yu. A. Ovchinnikov Institut of Bioorganic Chemistry, Moscow, Russia.

出版信息

J Gen Virol. 2003 Mar;84(Pt 3):727-732. doi: 10.1099/vir.0.18972-0.

DOI:10.1099/vir.0.18972-0

PMID:12604825

Abstract

Replication of tobacco mosaic virus (TMV) is connected with endoplasmic reticulum (ER)-associated membranes at early stages of infection. This study reports that TMV movement protein (MP)-specific protein kinases (PKs) associated with the ER of tobacco were capable of phosphorylating Thr(104) in TMV MP. The MP-specific PKs with apparent molecular masses of about 45-50 kDa and 38 kDa were revealed by gel PK assays. Two types of mutations were introduced in TMV MP gene of wild-type TMV U1 genome to substitute Thr(104) by neutral Ala or by negatively charged Asp. Mutation of Thr(104) to Ala did not affect the size of necrotic lesions induced by the mutant virus in Nicotiana tabacum Xanthi nc. plants. Conversely, mutation of Thr to Asp mimicking Thr(104) phosphorylation strongly inhibited cell-to-cell movement. The possible role of Thr(104) phosphorylation in TMV MP function is discussed.

摘要

烟草花叶病毒（TMV）的复制在感染早期与内质网（ER）相关膜相连。本研究报道，与烟草内质网相关的TMV运动蛋白（MP）特异性蛋白激酶（PKs）能够磷酸化TMV MP中的苏氨酸（Thr）104位点。通过凝胶PK分析揭示了表观分子量约为45 - 50 kDa和38 kDa的MP特异性PKs。在野生型TMV U1基因组的TMV MP基因中引入了两种类型的突变，用中性丙氨酸（Ala）或带负电荷的天冬氨酸（Asp）替代苏氨酸104位点。将苏氨酸104突变为丙氨酸不影响突变病毒在烟草品种Xanthi nc植株中诱导的坏死斑大小。相反，将苏氨酸突变为模拟苏氨酸104磷酸化的天冬氨酸强烈抑制了细胞间运动。本文讨论了苏氨酸104磷酸化在TMV MP功能中的可能作用。