Arabidopsis actin capping protein (AtCP) subunits have different expression patterns, and downregulation of AtCPB confers increased thermotolerance of Arabidopsis after heat shock stress.
As a heterodimer actin-binding protein, capping protein is composed of α and β subunits, and can stabilize the actin filament cytoskeleton by binding to F-actin ends to inhibit G-actin addition or loss from that end. Until now, studies on plant capping protein have focused on biochemical functions in vitro, and so the expression patterns and physiological functions of actin capping protein in Arabidopsis (AtCP) are poorly understood. In the present study, real-time quantitative PCR and Western blot analysis showed that although AtCP α and β subunits (i.e. AtCPA and AtCPB) were expressed in various tissues, their expression patterns were significantly different. GUS staining further indicated they were present in different parts of the same organs. We also demonstrated that the expression levels of both subunits were induced by heat shock stress. However, only the atcpβ-mutant showed enhanced thermotolerance, and confocal microscopy showed that the actin filaments of the atcpβ-mutant were much more complete than that in the wild-type and the atcpα-mutant after heat treatment at 45 °C for 40 and 45 min. In conclusion, these results demonstrated that AtCPA and AtCPB showed distinct expression patterns in vivo, and that downregulation of AtCPB conferred increased plant thermotolerance after heat shock stress.
Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: wangjuehot@hotmail.com.
Jue
J
Wang
Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Dong
D
Qian
Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Tingting
T
Fan
Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Honglei
H
Jia
Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: lizhean@lzu.edu.cn.
Lizhe
L
An
Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: xiangyun1661@126.com.
Yun
Y
Xiang
D051344:Actin Capping Proteins / Q000378:metabolism*; D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D015536:Down-Regulation; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D005838:Genotype; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D018869:Heat-Shock Response / Q000502:physiology*; D009154:Mutation; D013312:Stress, Physiological
D051344:Actin Capping Proteins; D029681:Arabidopsis Proteins; C577831:F-actin-capping protein subunit alpha, Arabidopsis; C577832:F-actin-capping protein subunit beta, Arabidopsis; D006360:Heat-Shock Proteins