The large GTpase dynamin regulates actin comet formation and movement in living cells

James D. Orth, E. W. Krueger, H. Cao, Mark A. McNiven

Research output: Contribution to journalArticlepeer-review

188 Scopus citations


The large GTPase dynamin (Dyn2) has been demonstrated by us and others to interact with several different actin-binding proteins. To define how Dyn2 might participate in actin dynamics in livings cells we have expressed green fluorescent protein (GFP)-tagged Dyn2 in cultured cells and observed labeling of comet-like vesicles and macropinosomes. The comet structures progressed with a constant velocity and were reminiscent of actin comets associated with motile vesicles in cells expressing type I phosphatidylinositol phosphate 5-kinases. Based on these observations we sought to determine whether Dyn2 is an integral component of actin comets. Cells expressing type I phosphatidylinositol phosphate 5-kinase and Dyn2-GFP revealed a prominent colocalization of Dyn2 and actin in comet structures. Interestingly, comet formation and motility were normal in cells expressing wild-type Dyn2-GFP but altered markedly in Dyn2 mutant-expressing cells. Dyn2K44A-GFP mutant cells displayed a significant reduction in comet number, length, velocity, and efficiency of movement. In contrast, comets in cells expressing Dyn2ΔPRD-GFP appeared dark and did not incorporate the mutant Dyn2 protein, indicating that the proline-rich domain (PRD) is required for Dyn2 recruitment. Further, these comets were significantly longer and slower than those in control cells. These findings demonstrate a role for Dyn2 in actin-based vesicle motility.

Original languageEnglish (US)
Pages (from-to)167-172
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number1
StatePublished - Jan 8 2002


  • Membrane trafficking
  • PIP5KI
  • Vesicle motility

ASJC Scopus subject areas

  • General


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