ITSN2L Interacts with and Negatively Regulates RABEP1

Int J Mol Sci. 2015 Nov 27;16(12):28242-54. doi: 10.3390/ijms161226091.


Intersectin-2Long (ITSN2L) is a multi-domain protein participating in endocytosis and exocytosis. In this study, RABEP1 was identified as a novel ITSN2L interacting protein using a yeast two-hybrid screen from a human brain cDNA library and this interaction, specifically involving the ITSN2L CC domain and RABEP1 CC3 regions, was further confirmed by in vitro GST (glutathione-S-transferase) pull-down and in vivo co-immunoprecipitation assays. Corroboratively, we observed that these two proteins co-localize in the cytoplasm of mammalian cells. Furthermore, over-expression of ITSN2L promotes RABEP1 degradation and represses RABEP1-enhanced endosome aggregation, indicating that ITSN2L acts as a negative regulator of RABEP1. Finally, we showed that ITSN2L and RABEP1 play opposite roles in regulating endocytosis. Taken together, our results indicate that ITSN2L interacts with RABEP1 and stimulates its degradation in regulation of endocytosis.

Keywords: ITSN2L; RABEP1; endocytosis; endosome; interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport / chemistry
  • Adaptor Proteins, Vesicular Transport / genetics
  • Adaptor Proteins, Vesicular Transport / metabolism*
  • Cell Line
  • Endocytosis / physiology
  • Gene Expression Regulation
  • Gene Knockdown Techniques
  • Humans
  • Immunoprecipitation
  • Intracellular Space / metabolism
  • Peptide Library
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Interaction Mapping
  • Protein Transport
  • Proteolysis
  • Two-Hybrid System Techniques
  • Vesicular Transport Proteins / chemistry
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*


  • Adaptor Proteins, Vesicular Transport
  • ITSN2 protein, human
  • Peptide Library
  • RABEP1 protein, human
  • Vesicular Transport Proteins