FMNL2 and -3 regulate Golgi architecture and anterograde transport downstream of Cdc42

Sci Rep. 2017 Aug 29;7(1):9791. doi: 10.1038/s41598-017-09952-1.

Abstract

The Rho-family small GTPase Cdc42 localizes at plasma membrane and Golgi complex and aside from protrusion and migration operates in vesicle trafficking, endo- and exocytosis as well as establishment and/or maintenance of cell polarity. The formin family members FMNL2 and -3 are actin assembly factors established to regulate cell edge protrusion during migration and invasion. Here we report these formins to additionally accumulate and function at the Golgi apparatus. As opposed to lamellipodia, Golgi targeting of these proteins required both their N-terminal myristoylation and the interaction with Cdc42. Moreover, Golgi association of FMNL2 or -3 induced a phalloidin-detectable actin meshwork around the Golgi. Importantly, functional interference with FMNL2/3 formins by RNAi or CRISPR/Cas9-mediated gene deletion invariably induced Golgi fragmentation in different cell lines. Furthermore, absence of these proteins led to enlargement of endosomes as well as defective maturation and/or sorting into late endosomes and lysosomes. In line with Cdc42 - recently established to regulate anterograde transport through the Golgi by cargo sorting and carrier formation - FMNL2/3 depletion also affected anterograde trafficking of VSV-G from the Golgi to the plasma membrane. Our data thus link FMNL2/3 formins to actin assembly-dependent functions of Cdc42 in anterograde transport through the Golgi apparatus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers
  • Cell Line
  • Endosomes / genetics
  • Endosomes / metabolism
  • Fluorescent Antibody Technique
  • Formins
  • Gene Expression
  • Gene Knockdown Techniques
  • Golgi Apparatus / metabolism*
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Lysosomes / genetics
  • Lysosomes / metabolism
  • Mice
  • Protein Binding
  • Protein Transport
  • Proteins / genetics
  • Proteins / metabolism*
  • Pseudopodia / metabolism
  • cdc42 GTP-Binding Protein / genetics
  • cdc42 GTP-Binding Protein / metabolism*

Substances

  • Biomarkers
  • FMNL2 protein, mouse
  • FMNL3 protein, mouse
  • Formins
  • Intracellular Signaling Peptides and Proteins
  • Proteins
  • cdc42 GTP-Binding Protein