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Chemical genetic identification of CDKL 5 substrates reveals its role in neuronal microtubule dynamics
Author(s) -
Baltussen Lucas L,
Negraes Priscilla D,
Silvestre Margaux,
Claxton Suzanne,
Moeskops Max,
Christodoulou Evangelos,
Flynn Helen R,
Snijders Ambrosius P,
Muotri Alysson R,
Ultanir Sila K
Publication year - 2018
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.15252/embj.201899763
Subject(s) - biology , microtubule , identification (biology) , microbiology and biotechnology , dynamics (music) , genetics , computational biology , ecology , physics , acoustics
Loss‐of‐function mutations in CDKL 5 kinase cause severe neurodevelopmental delay and early‐onset seizures. Identification of CDKL 5 substrates is key to understanding its function. Using chemical genetics, we found that CDKL 5 phosphorylates three microtubule‐associated proteins: MAP 1S, EB 2 and ARHGEF 2, and determined the phosphorylation sites. Substrate phosphorylations are greatly reduced in CDKL 5 knockout mice, verifying these as physiological substrates. In CDKL 5 knockout mouse neurons, dendritic microtubules have longer EB 3‐labelled plus‐end growth duration and these altered dynamics are rescued by reduction of MAP 1S levels through sh RNA expression, indicating that CDKL 5 regulates microtubule dynamics via phosphorylation of MAP 1S. We show that phosphorylation by CDKL 5 is required for MAP 1S dissociation from microtubules. Additionally, anterograde cargo trafficking is compromised in CDKL 5 knockout mouse dendrites. Finally, EB 2 phosphorylation is reduced in patient‐derived human neurons. Our results reveal a novel activity‐dependent molecular pathway in dendritic microtubule regulation and suggest a pathological mechanism which may contribute to CDKL 5 deficiency disorder.