A ubiquitin-based effector-to-inhibitor switch coordinates early brain, craniofacial, and skin development


The molecular mechanisms that coordinate patterning of the embryonic ectoderm into spatially distinct lineages to form the nervous system, epidermis, and neural crest-derived craniofacial structures are unclear. Here, biochemical disease-variant profiling reveals a posttranslational pathway that drives early ectodermal differentiation in the vertebrate head. The anteriorly expressed ubiquitin ligase CRL3-KLHL4 restricts signaling of the ubiquitous cytoskeletal regulator CDC42. This regulation relies on the CDC42-activating complex GIT1-βPIX, which CRL3-KLHL4 exploits as a substrate-specific co-adaptor to recognize and monoubiquitylate PAK1. Surprisingly, we find that ubiquitylation converts the canonical CDC42 effector PAK1 into a CDC42 inhibitor. Loss of CRL3-KLHL4 or a disease-associated KLHL4 variant reduce PAK1 ubiquitylation causing overactivation of CDC42 signaling and defective ectodermal patterning and neurulation. Thus, tissue-specific restriction of CDC42 signaling by a ubiquitin-based effector-to-inhibitor is essential for early face, brain, and skin formation, revealing how cell-fate and morphometric changes are coordinated to ensure faithful organ development. © 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.

Authors Asmar AJ, Abrams SR, Hsin J, Collins JC, Yazejian RM, Wu Y, Cho J, Doyle AD, Cinthala S, Simon M, van Jaarsveld RH, Beck DB, Kerosuo L, Werner A
Journal Nature communications
Publication Date 2023 Jul 26;14(1):4499
PubMed 37495603
PubMed Central PMC10371987
DOI 10.1038/s41467-023-40223-y

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