CRL5-dependent regulation of the small GTPases ARL4C and ARF6 controls hippocampal morphogenesis

Proc Natl Acad Sci U S A. 2020 Sep 15;117(37):23073-23084. doi: 10.1073/pnas.2002749117. Epub 2020 Sep 1.


The small GTPase ARL4C participates in the regulation of cell migration, cytoskeletal rearrangements, and vesicular trafficking in epithelial cells. The ARL4C signaling cascade starts by the recruitment of the ARF-GEF cytohesins to the plasma membrane, which, in turn, bind and activate the small GTPase ARF6. However, the role of ARL4C-cytohesin-ARF6 signaling during hippocampal development remains elusive. Here, we report that the E3 ubiquitin ligase Cullin 5/RBX2 (CRL5) controls the stability of ARL4C and its signaling effectors to regulate hippocampal morphogenesis. Both RBX2 knockout and Cullin 5 knockdown cause hippocampal pyramidal neuron mislocalization and development of multiple apical dendrites. We used quantitative mass spectrometry to show that ARL4C, Cytohesin-1/3, and ARF6 accumulate in the RBX2 mutant telencephalon. Furthermore, we show that depletion of ARL4C rescues the phenotypes caused by Cullin 5 knockdown, whereas depletion of CYTH1 or ARF6 exacerbates overmigration. Finally, we show that ARL4C, CYTH1, and ARF6 are necessary for the dendritic outgrowth of pyramidal neurons to the superficial strata of the hippocampus. Overall, we identified CRL5 as a key regulator of hippocampal development and uncovered ARL4C, CYTH1, and ARF6 as CRL5-regulated signaling effectors that control pyramidal neuron migration and dendritogenesis.

Keywords: ARF6; ARL4C; CRL5; hippocampal development; pyramidal neuron migration.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • ADP-Ribosylation Factor 6
  • ADP-Ribosylation Factors / metabolism*
  • Animals
  • Cell Membrane / metabolism
  • Cell Movement / physiology
  • Cullin Proteins / metabolism*
  • Dendrites / metabolism
  • Guanine Nucleotide Exchange Factors / metabolism
  • Hippocampus / metabolism*
  • Mice
  • Monomeric GTP-Binding Proteins / metabolism*
  • Morphogenesis / physiology*
  • Neurogenesis / physiology
  • Pyramidal Cells / metabolism
  • Signal Transduction / physiology
  • Ubiquitin-Protein Ligases / metabolism


  • ADP-Ribosylation Factor 6
  • Arl4c protein, mouse
  • Cullin Proteins
  • Guanine Nucleotide Exchange Factors
  • cytohesin-1
  • Ubiquitin-Protein Ligases
  • ADP-Ribosylation Factors
  • ARF6 protein, human
  • Arf6 protein, mouse
  • Monomeric GTP-Binding Proteins