The X-linked intellectual disability gene product and E3 ubiquitin ligase KLHL15 degrades doublecortin proteins to constrain neuronal dendritogenesis [Molecular Bases of Disease]

Alexandros G.Sfakianakis shared this article with you from Inoreader The X-linked intellectual disability gene product and E3 ubiquitin ligase KLHL15 degrades doublecortin proteins to constrain neuronal dendritogenesis [Molecular Bases of Disease] Μέσω JBC Papers in Press Proper brain development and function requires finely controlled mechanisms for protein turnover and disruption of genes involved in proteostasis is a common cause of neurodevelopmental disorders. Kelch-like 15 (KLHL15) is a substrate adaptor for cullin3 (Cul3)-containing E3 ubiquitin ligases and KLHL15 gene mutations were recently described as a cause of severe X-linked intellectual disability (XLID). Her e, we used a bioinformatics approach to identify a family of neuronal microtubule-associated proteins (MAPs) as KLHL15 substrates, which are themselves critical for early brain development. We biochemically validated doublecortin (DCX), also an X-linked disease protein, and doublecortin-like kinase 1 and 2 (DCLK1/2) as bona fide KLHL15 interactors and mapped KLHL15 interaction regions to their tandem DCX domains. Shared with two previously identified KLHL15 substrates, a FRY tripeptide at the C-terminal edge of the second DCX domain is necessary for KLHL15-mediated ubiquitination of DCX and DCLK1/2 and subsequent proteasomal degradation. Conversely, silencing endogenous KLHL15 markedly stabilizes these DCX domain-containing proteins and prolongs their half-life. Functionally, overexpression of KLHL15 in the presence of wild-type DCX reduces dendritic complexity of cultured hippocampal neurons, whereas neurons expressing FRY-mutant DCX are resistant to KLHL15. Collectively, our findi ngs highlight the critical importance of the E3 ubiquitin ligase adaptor KLHL15 in proteostasis of neuronal MAPs and identify a regulatory network important for development of the mammalian nervous system. View on the web Inoreader. Take back control of your news feed. Follow us on Twitter and Facebook.