Cell transit analysis of ligand-induced stiffening of polymorphonuclear leukocytes.
A mathematical treatment of the mechanical behavior of transiently bonded polymer networks is used to interpret measurements of the pressure-induced passage of plant cells through microporous membranes. Cell transit times are inferred to be proportional to the instantaneous shear modulus of the cell cortex, a parameters that we then relate to properties of the cortical F-actin matrix. These theoretical results are used to analyze published data on chemoattractant-induced changes of rigidity of polymorphonuclear leukocytes. We thereby rationalize previously noted, peculiar, power-law logarithmic dependences of transit time on ligand concentration. As a consequence, we are able to deduce a linear relationship between the extent of F-actin polymerization and the logarithm of the chemoattractant concentration. The latter is examined with regard to the G-protein activation that is known to occur when chemoattractants bind to receptors on the surfaces of polymorphonuclear cells.
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Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA. rjn@cu.nih.gov
D000199:Actins / Q000502:physiology; D055592:Biophysical Phenomena; D001703:Biophysics; D001704:Biopolymers / Q000502:physiology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects / Q000502:physiology; D003599:Cytoskeleton / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004548:Elasticity; D019204:GTP-Binding Proteins / Q000502:physiology; D006801:Humans; D006874:Hydrostatic Pressure; D066298:In Vitro Techniques; D007700:Kinetics; D008024:Ligands; D008851:Micropore Filters; D008954:Models, Biological; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000008:administration & dosage; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D014783:Viscosity
D000199:Actins; D001704:Biopolymers; D008024:Ligands; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019204:GTP-Binding Proteins