F-actin network formation in tethers and in pseudopods stimulated by chemoattractant.


Journal Article

Micropipets are used either to deliver a given concentration of the chemoattractant N-formyl-methionyl-leucyl-phenylalanine (fMLP) to a local region of a human neutrophil or to create a membrane tether. Pseudopods, which have a cylindrical shape and grow at a constant rate, are formed in either case. After reaching a maximum extension, they retract, even in the presence of chemoattractant. As a pseudopod grows, cell granules begin to penetrate the pseudopod region to a "boundary" that defines a distance to the pseudopod's leading edge that is almost constant. The exclusion of granules from this domain indicates that it is filled with a dense network. The formation of this network involves the plasma membrane because pseudopod growth ceases when a membrane tether is pulled away from the leading edge. The rate of pseudopod growth depends on fMLP concentration just as the number of occupied N-formyl peptide receptors depends on this concentration. The experimental data are explained by assuming that F-actin network is formed next to the plasma membrane. The newly formed network displaces the membrane and the dominant process in the network region then becomes F-actin depolymerization. The rate of pseudopod growth is determined by the rate of the process leading to network formation. This process is apparently an enzymatic type of reaction. It has a positive enthalpy change and, therefore, is endothermic.

Full Text

Duke Authors

Cited Authors

  • Zhelev, DV; Alteraifi, AM; Hochmuth, RM

Published Date

  • January 1, 1996

Published In

Volume / Issue

  • 35 / 4

Start / End Page

  • 331 - 344

PubMed ID

  • 8956004

Pubmed Central ID

  • 8956004

Electronic International Standard Serial Number (EISSN)

  • 1097-0169

International Standard Serial Number (ISSN)

  • 0886-1544

Digital Object Identifier (DOI)

  • 10.1002/(sici)1097-0169(1996)35:4<331::aid-cm5>3.0.co;2-9


  • eng