Top

Research Article

Split Viewer

Mol. Cells 2013; 36(6): 564-570

Published online December 31, 2013

https://doi.org/10.1007/s10059-013-0266-8

© The Korean Society for Molecular and Cellular Biology

Structural and Functional Characterization of Arabidopsis GSK3-like Kinase AtSK12

Ji-Hyun Youn, Tae-Woo Kim, Eun-Ji Kim, Shuolei Bu,Seong-Ki Kim, Zhi-Yong Wang, and Tae-Wuk Kim

1Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791, Korea, 2Department of Life Science, College of Natural Sciences, Chungang University, Seoul 156-756, Korea, 3Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA, 4Natural Science Institute, Hanyang University, Seoul 133-791, Korea

Received: September 17, 2013; Revised: October 14, 2013; Accepted: November 5, 2013

Abstract

Plant GSK3-like kinases are key regulators that modulate a broad range of physiological processes such as cell growth, stomatal and flower development, responses for abiotic and biotic stress, and carbohydrate metabolism. Arabidopsis Shaggy/GSK3-like kinases (AtSK) consist of ten members that are classified into four subfamilies (I~IV). Only one of these Arabidopsis GSK3s, BIN2 (also named AtSK21), has been characterized by biochemical and genetic studies. BIN2 acts as a negative regulator in brassinosteroid (BR) signaling that controls cell growth and differentiation. Recent studies suggest that at least seven AtSKs are involved in BR signaling. However, specificities
for the substrates and the functional differences of each member of the family remain to be determined. Here we report structural characteristics and distinct function of AtSK12 compared with BIN2. AtSK12 has a longer N-terminal extension, which is absent in BIN2. Transgenic plants overexpressing the AtSK12 mutant carrying deletion of Nterminal region display more severe dwarf phenotypes than those of the wild-type AtSK12. Microscopic analysis reveals that N-terminal-deleted AtSK12 accumulates in the nucleus. This implies that structural difference in the Nterminal region of AtSK members contributes to their subcellular localization. In contrast to BIN2, overexpression of AtSK12 does not cause a stomatal cluster. Furthermore, we show that YODA MAPKKK, which controls stomatal
development, interacts with BIN2 but not with AtSK12. Our results suggest that AtSK12 mediates BR-regulated cell growth but not stomatal development while BIN2 regulates both processes. Our study provides evidence that different GSK3 members can have overlapping but non-identical functions.

Keywords brassinosteroids, growth, GSK3-like kinase, MAP kinase kinase kinase, stomatal development

Article

Research Article

Mol. Cells 2013; 36(6): 564-570

Published online December 31, 2013 https://doi.org/10.1007/s10059-013-0266-8

Copyright © The Korean Society for Molecular and Cellular Biology.

Structural and Functional Characterization of Arabidopsis GSK3-like Kinase AtSK12

Ji-Hyun Youn, Tae-Woo Kim, Eun-Ji Kim, Shuolei Bu,Seong-Ki Kim, Zhi-Yong Wang, and Tae-Wuk Kim

1Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791, Korea, 2Department of Life Science, College of Natural Sciences, Chungang University, Seoul 156-756, Korea, 3Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA, 4Natural Science Institute, Hanyang University, Seoul 133-791, Korea

Received: September 17, 2013; Revised: October 14, 2013; Accepted: November 5, 2013

Abstract

Plant GSK3-like kinases are key regulators that modulate a broad range of physiological processes such as cell growth, stomatal and flower development, responses for abiotic and biotic stress, and carbohydrate metabolism. Arabidopsis Shaggy/GSK3-like kinases (AtSK) consist of ten members that are classified into four subfamilies (I~IV). Only one of these Arabidopsis GSK3s, BIN2 (also named AtSK21), has been characterized by biochemical and genetic studies. BIN2 acts as a negative regulator in brassinosteroid (BR) signaling that controls cell growth and differentiation. Recent studies suggest that at least seven AtSKs are involved in BR signaling. However, specificities
for the substrates and the functional differences of each member of the family remain to be determined. Here we report structural characteristics and distinct function of AtSK12 compared with BIN2. AtSK12 has a longer N-terminal extension, which is absent in BIN2. Transgenic plants overexpressing the AtSK12 mutant carrying deletion of Nterminal region display more severe dwarf phenotypes than those of the wild-type AtSK12. Microscopic analysis reveals that N-terminal-deleted AtSK12 accumulates in the nucleus. This implies that structural difference in the Nterminal region of AtSK members contributes to their subcellular localization. In contrast to BIN2, overexpression of AtSK12 does not cause a stomatal cluster. Furthermore, we show that YODA MAPKKK, which controls stomatal
development, interacts with BIN2 but not with AtSK12. Our results suggest that AtSK12 mediates BR-regulated cell growth but not stomatal development while BIN2 regulates both processes. Our study provides evidence that different GSK3 members can have overlapping but non-identical functions.

Keywords: brassinosteroids, growth, GSK3-like kinase, MAP kinase kinase kinase, stomatal development

Mol. Cells
Nov 30, 2022 Vol.45 No.11, pp. 763~867
COVER PICTURE
Naive (cyan) and axotomized (magenta) retinal ganglion cell axons in Xenopus tropicalis (Choi et al., pp. 846-854).

Share this article on

  • line
  • mail

Related articles in Mol. Cells

Molecules and Cells

eISSN 0219-1032
qr-code Download