Trabid patient mutations impede the axonal trafficking of adenomatous polyposis coli to disrupt neurite growth.
Daniel FrankMaria BergamascoMichael J MlodzianoskiAndrew KuehEllen TsuiCathrine HallGeorgios KastrappisAnne Kathrin VossCatriona A McleanMaree C FauxKelly L RogersBang M TranElizabeth VincanDavid KomanderGrant DewsonHoanh TranPublished in: eLife (2023)
ZRANB1 (human Trabid) missense mutations have been identified in children diagnosed with a range of congenital disorders including reduced brain size, but how Trabid regulates neurodevelopment is not understood. We have characterized these patient mutations in cells and mice to identify a key role for Trabid in the regulation of neurite growth. One of the patient mutations flanked the catalytic cysteine of Trabid and its deubiquitylating (DUB) activity was abrogated. The second variant retained DUB activity, but failed to bind STRIPAK, a large multiprotein assembly implicated in cytoskeleton organization and neural development. Zranb1 knock-in mice harboring either of these patient mutations exhibited reduced neuronal and glial cell densities in the brain and a motor deficit consistent with fewer dopaminergic neurons and projections. Mechanistically, both DUB-impaired and STRIPAK-binding-deficient Trabid variants impeded the trafficking of adenomatous polyposis coli (APC) to microtubule plus-ends. Consequently, the formation of neuronal growth cones and the trajectory of neurite outgrowth from mutant midbrain progenitors were severely compromised. We propose that STRIPAK recruits Trabid to deubiquitylate APC, and that in cells with mutant Trabid, APC becomes hyperubiquitylated and mislocalized causing impaired organization of the cytoskeleton that underlie the neuronal and developmental phenotypes.
Keyphrases
- case report
- induced apoptosis
- escherichia coli
- cerebral ischemia
- cell cycle arrest
- endothelial cells
- young adults
- resting state
- white matter
- single cell
- stem cells
- cell death
- spinal cord
- oxidative stress
- type diabetes
- multiple sclerosis
- endoplasmic reticulum stress
- high fat diet induced
- dna methylation
- induced pluripotent stem cells
- adipose tissue
- functional connectivity
- subarachnoid hemorrhage
- living cells
- mesenchymal stem cells
- optical coherence tomography
- dna binding