Structural and biochemical insights into the activation mechanisms of germinal center kinase OSR1.
The oxidative stress-responsive 1 (OSR1) kinase belongs to the mammalian STE20-like kinase family. OSR1 is activated by with no lysine [K] (WNKs) kinases, and then it phosphorylates cation-coupled Cl-cotransporters, regulating ion homeostasis and cell volume in mammalian cells. However, the specific mechanisms of OSR1 activation remains poorly defined, largely due to its extremely low basal activity. Here, we dissect in detail the regulatory mechanisms of OSR1 activation from the aspects of autoinhibition, upstream kinase WNK, and the newly identified master regulator mouse protein-25 (MO25). Based on our structural and biochemical studies, we propose a "double lock" model, accounting for the tight autoinhibition of OSR1, an effect that has to be removed by WNK before MO25 further activates OSR1. Particularly, the conserved C-terminal (CCT) domain and αAL helix act together to strongly suppress OSR1 basal activity. WNKs bind to the CCT and trigger its conformational rearrangement to release the kinase domain of OSR1, allowing for MO25 binding and full activation. Finally, the regulatory mechanisms of OSR1 activation were further corroborated by cellular studies of OSR1-regulated cell volume control through WNK-OSR1 signaling pathway. Collectively, these results provide insights into the OSR1 kinase activation to facilitate further functional study.
From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and.
Chuanchuan
C
Li
From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and.
Miao
M
Feng
From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and School of Life Sciences and Technology, Tongji University, Shanghai 200092, China.
Zhubing
Z
Shi
From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and.
Qian
Q
Hao
From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and.
Xiaomin
X
Song
From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and.
Wenjia
W
Wang
From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and.
Yun
Y
Zhao
From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and jiaoshi@sibcb.ac.cn.
Shi
S
Jiao
From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China and zczhou@sibcb.ac.cn.
Zhaocai
Z
Zhou
D000595:Amino Acid Sequence; D002135:Calcium-Binding Proteins / Q000737:chemistry; D020134:Catalytic Domain; D048429:Cell Size; D004789:Enzyme Activation; D057809:HEK293 Cells; D006706:Homeostasis; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry; D015778:Minor Histocompatibility Antigens; D008969:Molecular Sequence Data; D011485:Protein Binding; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000502:physiology; D000076204:WNK Lysine-Deficient Protein Kinase 1
C540569:CAB39 protein, human; D002135:Calcium-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D015778:Minor Histocompatibility Antigens; C118135:OXSR1 protein, human; D017346:Protein Serine-Threonine Kinases; D000076204:WNK Lysine-Deficient Protein Kinase 1; C498743:WNK1 protein, human
Enzyme Mechanism; Homeostasis; OSR1; Protein Kinase; Protein Structure; Protein-Protein Interaction