Arp2 depletion inhibits sheet-like protrusions but not linear protrusions of fibroblasts and lymphocytes

Cell Motil Cytoskeleton. 2008 Nov;65(11):904-22. doi: 10.1002/cm.20312.


The Arp2/3 complex-mediated assembly and protrusion of a branched actin network at the leading edge occurs during cell migration, although some studies suggest it is not essential. In order to test the role of Arp2/3 complex in leading edge protrusion, Swiss 3T3 fibroblasts and Jurkat T cells were depleted of Arp2 and evaluated for defects in cell morphology and spreading efficiency. Arp2-depleted fibroblasts exhibit severe defects in formation of sheet-like protrusions at early time points of cell spreading, with sheet-like protrusions limited to regions along the length of linear protrusions. However, Arp2-depleted cells are able to spread fully after extended times. Similarly, Arp2-depleted Jurkat T lymphocytes exhibit defects in spreading on anti-CD3. Interphase Jurkats in suspension are covered with large ruffle structures, whereas mitotic Jurkats are covered by finger-like linear protrusions. Arp2-depleted Jurkats exhibit defects in ruffle assembly but not in assembly of mitotic linear protrusions. Similarly, Arp2-depletion has no effect on the highly dynamic linear protrusion of another suspended lymphocyte line. We conclude that Arp2/3 complex plays a significant role in assembly of sheet-like protrusions, especially during early stages of cell spreading, but is not required for assembly of a variety of linear actin-based protrusions.

Publication types

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

MeSH terms

  • 3T3 Cells
  • Actin-Related Protein 2 / metabolism*
  • Animals
  • Cell Adhesion
  • Cell Movement
  • Cell Surface Extensions / metabolism*
  • Cells, Cultured
  • Fibroblasts / cytology
  • Fibroblasts / metabolism*
  • Humans
  • Jurkat Cells
  • Lymphocytes / cytology
  • Lymphocytes / metabolism*
  • Lymphoma
  • Mice
  • Microvilli / metabolism
  • Mitosis
  • Pseudopodia
  • Transfection


  • Actin-Related Protein 2