Mammalian Mon2/Ysl2 regulates endosome-to-Golgi trafficking but possesses no guanine nucleotide exchange activity toward Arl1 GTPase

Sci Rep. 2013 Nov 28;3:3362. doi: 10.1038/srep03362.


Arl1 is a member of Arf family small GTPases that is essential for the organization and function of Golgi complex. Mon2/Ysl2, which shares significant homology with Sec7 family Arf guanine nucleotide exchange factors, was poorly characterized in mammalian cells. Here, we report the first in depth characterization of mammalian Mon2. We found that Mon2 localized to trans-Golgi network which was dependent on both its N and C termini. The depletion of Mon2 did not affect the Golgi localized or cellular active form of Arl1. Furthermore, our in vitro assay demonstrated that recombinant Mon2 did not promote guanine nucleotide exchange of Arl1. Therefore, our results suggest that Mon2 could be neither necessary nor sufficient for the guanine nucleotide exchange of Arl1. We demonstrated that Mon2 was involved in endosome-to-Golgi trafficking as its depletion accelerated the delivery of furin and CI-M6PR to Golgi after endocytosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP-Ribosylation Factors / metabolism*
  • Animals
  • Cell Line
  • Chlorocebus aethiops
  • Endocytosis / physiology
  • Endosomes / metabolism*
  • Furin / metabolism
  • Golgi Apparatus / metabolism*
  • Guanine Nucleotide Exchange Factors / genetics
  • Guanine Nucleotide Exchange Factors / metabolism
  • HeLa Cells
  • Humans
  • Membrane Proteins / metabolism*
  • Protein Transport / genetics*
  • Proton-Translocating ATPases / genetics
  • Proton-Translocating ATPases / metabolism*
  • RNA Interference
  • RNA, Small Interfering
  • Receptor, IGF Type 2 / metabolism


  • Guanine Nucleotide Exchange Factors
  • MON2 protein, human
  • Membrane Proteins
  • RNA, Small Interfering
  • Receptor, IGF Type 2
  • Sec7 guanine nucleotide exchange factors
  • cation-dependent mannose-6-phosphate receptor
  • Furin
  • ADP-ribosylation factor related proteins
  • Proton-Translocating ATPases
  • ADP-Ribosylation Factors