1. The SH2 domain and kinase activity of JAK2 target JAK2 to centrosome and regulate cell growth and centrosome amplification
- Author
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Aashirwad Shahi, Jacob Kahle, Chandler Hopkins, and Maria Diakonova
- Subjects
Centrosomes ,Science ,Protein domains ,Research and Analysis Methods ,Biochemistry ,Tyrosine Kinases ,Cell Line ,src Homology Domains ,Interferon-gamma ,hemic and lymphatic diseases ,Chlorocebus aethiops ,Genetics ,STAT5 Transcription Factor ,Point Mutation ,Animals ,Humans ,Cell Cycle and Cell Division ,Molecular Biology Techniques ,Signal Amplification ,Molecular Biology ,Cell Proliferation ,Centrosome ,Multidisciplinary ,Biology and Life Sciences ,Proteins ,food and beverages ,Cell Biology ,Cell Cycle Checkpoints ,Janus Kinase 2 ,SH2 domains ,Enzymes ,Protein Transport ,Cell Processes ,Signal Processing ,Mutation ,COS Cells ,Enzymology ,Mutagenesis, Site-Directed ,Medicine ,Engineering and Technology ,Cellular Structures and Organelles ,Protein Kinases ,hormones, hormone substitutes, and hormone antagonists ,Research Article ,Cloning - Abstract
JAK2 is cytokine-activated non-receptor tyrosine kinase. Although JAK2 is mainly localized at the plasma membrane, it is also present on the centrosome. In this study, we demonstrated that JAK2 localization to the centrosome depends on the SH2 domain and intact kinase activity. We created JAK2 mutants deficient in centrosomal localization ΔSH2, K882E and (ΔSH2, K882E). We showed that JAK2 WT clone strongly enhances cell proliferation as compared to control cells while JAK2 clones ΔSH2, K882E and (ΔSH2, K882E) proliferate slower than JAK2 WT cells. These mutant clones also progress much slower through the cell cycle as compared to JAK2 WT clone and the enhanced proliferation of JAK2 WT cells is accompanied by increased S −> G2 progression. Both the SH2 domain and the kinase activity of JAK2 play a role in prolactin-dependent activation of JAK2 substrate STAT5. We showed that JAK2 is an important regulator of centrosome function as the SH2 domain of JAK2 regulates centrosome amplification. The cells overexpressing ΔSH2 and (ΔSH2, K-E) JAK2 have almost three-fold the amplified centrosomes of WT cells. In contrast, the kinase activity of JAK2 is dispensable for centrosome amplification. Our observations provide novel insight into the role of SH2 domain and kinase activity of JAK2 in centrosome localization of JAK2 and in the regulation of cell growth and centrosome biogenesis.
- Published
- 2022