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Updated: Jun 7, 2026

Visualizing the Actin and Microtubule Cytoskeletons at the B-cell Immune Synapse Using Stimulated Emission Depletion (STED) Microscopy
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Hem-1: putting the "WAVE" into actin polymerization during an immune response

Heon Park1, Maia M Chan, Brian M Iritani

  • 1Department of Comparative Medicine, University of Washington, Seattle, WA 98195-7190, USA. heonp@uw.edu

FEBS Letters
|October 26, 2010
PubMed

Most active processes by immune cells including adhesion, migration, and phagocytosis require the coordinated polymerization and depolymerization of filamentous actin (F-actin), which is an essential component of the actin cytoskeleton. This review focuses on a newly characterized hematopoietic cell-specific actin regulatory protein called hematopoietic protein-1 [Hem-1, also known as Nck-associated protein 1-like (Nckap1l or Nap1l)]. Hem-1 is a component of the "WAVE [WASP (Wiskott-Aldrich syndrome protein)-family verprolin homologous protein]" complex, which signals downstream of activated Rac to stimulate F-actin polymerization in response to immuno-receptor signaling. Genetic studies in cell lines and in mice suggest that Hem-1 regulates F-actin polymerization in hematopoietic cells, and may be essential for most active processes dependent on reorganization of the actin cytoskeleton in immune cells.

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