The motor of leukocytes

T. P. Stossel, J. H. Hartwig, H. L. Yin, F. S. Southwick, K. S. Zaner

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


The movements of leukocytes involve extension, flow, and contraction of a margin of organelle-excluding cytoplasm. Actin is the principal structural component of this region. This paper reviews evidence that the expansion of cortical cytoplasm can result from the growth of actin polymers into an orthogonal network in which actin fibers branch perpendicularly under the influence of actin-binding protein. Flow occurs when actin filaments are disassembled and severed. The assembly and fragmentation of actin are regulated by actin-modulating proteins such as profilin, which sequesters actin monomers, acumentin, which binds to the slow-growing end of actin fibers, and gelsolin, a calcium-regulated protein that binds to the fast-growing end of actin polymers and severe actin filaments. Contraction of the actin network is caused by myosin, the assembly and activity of which are regulated by its state of phosphorylation, which is in turn controlled by phosphorylating and dephosphorylating enzymes and by calmodulin and calcium. Present information leads to the prediction that intracellular calcium gradients guide cytoplasmic extension is toward regions of low cytoplasmic free calcium.

Original languageEnglish (US)
Pages (from-to)2760-2763
Number of pages4
JournalFederation Proceedings
Issue number12
StatePublished - 1984

ASJC Scopus subject areas

  • General Medicine


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