Colchicine-induced stimulation of PMN motility related to cytoskeletal changes in actin, alpha-actinin, and myosin.
Colchicine-induced stimulation of polymorphonuclear leukocyte (PMN) locomotion is an interesting model because extension of blebs at the front occurs at a rate (about 2.4 microns/s) which is far above that reported for growth of actin filaments. The following cytoskeletal changes were observed in colchicine-treated PMNs: (1) a small increase in cytoskeleton-associated actin was noted, as well as a somewhat more pronounced increase in cytoskeleton-associated alpha-actinin, as compared with untreated or DMSO-treated controls. There was, however, no measurable increase in F-actin as determined by NBD-phallacidin binding; (2) the values for the ratio (alpha-actinin/actin) are lower in PMNs treated with colchicine for 30 min, as compared with PMNs stimulated with fNLPNTL for 1 minute (non-polar ruffling cells) or 30 min (polarized locomoting cells); thus, this ratio may depend on the type of PMN motility; (3) in polarized PMNs F-actin was mainly located linearly all along the cell membrane; there was more intense staining at the front of the cells; (4) alpha-actinin appeared to colocalize with F-actin at the leading front, but not with F-actin at the tail of polarized cells; (5) myosin was preferentially found at the rear part of polarized cells but not or only to a small extent at the front. Our data indicate a close functional correlation between microtubules and microfilaments. We speculate that F-actin in combination with alpha-actinin promotes expansion of pseudopods, whereas myosin combined with F-actin promotes contraction.(ABSTRACT TRUNCATED AT 250 WORDS)
Keller
H U
HU
Institute of Pathology, University of Bern, Switzerland.
Niggli
V
V
D000185:Actinin / Q000187:drug effects* / Q000378:metabolism; D000199:Actins / Q000187:drug effects* / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D003078:Colchicine / Q000494:pharmacology*; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D009218:Myosins / Q000187:drug effects* / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D014404:Tubulin / Q000187:drug effects / Q000378:metabolism
D000199:Actins; D014404:Tubulin; D000185:Actinin; D009218:Myosins; D003078:Colchicine