LF2 phosphorylation of the CDKL5 activation loop controls CDKL5’s activity

ABSTRACT: Cdkl5 Deficiency Disorder (CDD) is caused by variants in the protein kinase CDKL5, leading to symptoms such as seizures, developmental delay, and severe intellectual disability. The Chlamydomonas homologue of human CDKL5 is the flagellar protein LF5, whose absence results in a long flagella phenotype. We found that mouse CDKL5 similarly localizes within cilia, and its loss causes long cilia. Chlamydomonas cells lacking CDKL5 exhibit altered flagellar waveforms and reduced motility. CDKL5 kinase activity is essential for flagella length control and proper localization as a kinase-dead mutant, CDKL5K33R, fails to rescue the long flagella phenotype and does not properly localize to the proximal end of flagella. In wild-type cells, CDKL5 is highly phosphorylated at residues S162, T164, and Y166 within its activation loop and can undergo autophosphorylation in vitro. Interestingly, CDKL5 lacking kinase activity maintains similar phosphorylation at these residues. However, CDKL5 isolated from cells that lack the protein kinase LF2 has reduced activation loop phosphorylation, diminished autophosphorylation capacity, and altered ciliary localization, suggesting that LF2 phosphorylates CDKL5’s activation loop to regulate its kinase activity. Disruption of Cdk20, the mouse ortholog of LF2, likewise alters the ciliary localization of Cdkl5 in primary cilia. CDKL5 likely regulates intraflagellar transport (IFT) as the loss CDKL5 increased the ciliary abundance of IFT proteins while decreasing the phosphorylation of IFT74.

INSTRUMENT(S):

ORGANISM(S): Chlamydomonas Reinhardtii

TISSUE(S): Cilium

DISEASE(S): Developmental And Epileptic Encephalopathy 2,Neurodevelopmental Abnormality

SUBMITTER: Gregory Pazour  

LAB HEAD: Gregory Pazour

PROVIDER: PXD068782 | Pride | 2025-11-15

REPOSITORIES: Pride