Orchestration of microtubules and the actin cytoskeleton in trichome cell shape determination by a plant-unique kinesin.
Microtubules (MTs) and actin filaments (F-actin) function cooperatively to regulate plant cell morphogenesis. However, the mechanisms underlying the crosstalk between these two cytoskeletal systems, particularly in cell shape control, remain largely unknown. In this study, we show that introduction of the MyTH4-FERM tandem into KCBP (kinesin-like calmodulin-binding protein) during evolution conferred novel functions. The MyTH4 domain and the FERM domain in the N-terminal tail of KCBP physically bind to MTs and F-actin, respectively. During trichome morphogenesis, KCBP distributes in a specific cortical gradient and concentrates at the branching sites and the apexes of elongating branches, which lack MTs but have cortical F-actin. Further, live-cell imaging and genetic analyses revealed that KCBP acts as a hub integrating MTs and actin filaments to assemble the required cytoskeletal configuration for the unique, polarized diffuse growth pattern during trichome cell morphogenesis. Our findings provide significant insights into the mechanisms underlying cytoskeletal regulation of cell shape determination.
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Juan
J
Tian
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Libo
L
Han
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Zhidi
Z
Feng
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Guangda
G
Wang
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Weiwei
W
Liu
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Yinping
Y
Ma
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Yanjun
Y
Yu
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Zhaosheng
Z
Kong
D008841:Actin Cytoskeleton / Q000378:metabolism*; D017360:Arabidopsis / Q000166:cytology* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism*; D048430:Cell Shape; D008870:Microtubules / Q000378:metabolism*; D059828:Plant Cells / Q000502:physiology*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D064201:Trichomes / Q000166:cytology*
D029681:Arabidopsis Proteins; D002148:Calmodulin-Binding Proteins; C099551:KCBP protein, Arabidopsis
actin filaments; arabidopsis; cell biology; cell shape determination; kinesin; microtubules; plant biology; trichome