Regulation of dynamin-2 assembly-disassembly and function through the SH3A domain of intersectin-1s

J Cell Mol Med. 2011 Nov;15(11):2364-76. doi: 10.1111/j.1582-4934.2010.01226.x.


Intersectin-1s (ITSN-1s), a five Src homology 3 (SH3) domain-containing protein, is critically required for caveolae and clathrin-mediated endocytosis (CME), due to its interactions with dynamin (dyn). Of the five SH3A-E domains, SH3A is unique because of its high affinity for dyn and potent inhibition of CME. However, the molecular mechanism by which SH3A integrates in the overall function of ITSN-1s to regulate the endocytic process is not understood. Using biochemical and functional approaches as well as high-resolution electron microscopy, we show that SH3A exogenously expressed in human lung endothelial cells caused abnormal endocytic structures, distorted caveolae clusters, frequent staining-dense rings around the caveolar necks and 60% inhibition of caveolae internalization. In vitro studies further revealed that SH3A, similar to full-length ITSN-1s stimulates dyn2 oligomerization and guanosine triphosphatase (GTP)ase activity, effects not detected when other SH3 domains of ITSN-1s were used as controls. Strikingly, in the presence of SH3A, dyn2-dyn2 interactions are stabilized and despite continuous GTP hydrolysis, dyn2 oligomers cannot disassemble. SH3A may hold up caveolae release from the plasma membrane and formation of free-transport vesicles, by prolonging the lifetime of assembled dyn2. Altogether, our results indicate that ITSN-1s, via its SH3A has the unique ability to regulate dyn2 assembly-disassembly and function during endocytosis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport / metabolism*
  • Animals
  • Caveolae / physiology*
  • Caveolae / ultrastructure
  • Cell Membrane / metabolism
  • Cell Membrane / physiology
  • Clathrin / metabolism
  • Dynamin II / metabolism
  • Dynamin II / physiology*
  • Endocytosis*
  • Endothelial Cells
  • GTP Phosphohydrolases / metabolism
  • Humans
  • Lung
  • Rats
  • src Homology Domains


  • Adaptor Proteins, Vesicular Transport
  • Clathrin
  • ITSN1 protein, human
  • GTP Phosphohydrolases
  • Dynamin II