TY - JOUR
T1 - Chemoattractant-stimulated polymorphonuclear leukocytes contain two populations of actin filaments that differ in their spatial distributions and relative stabilities
AU - Cassimeris, Lynne
AU - McNeill, Helen
AU - Zigmond, Sally H.
PY - 1990/4
Y1 - 1990/4
N2 - Chemoattractants stimulate actin polymerization in lamellipodia of polymorphonuclear leukocytes. We find that removal of chemoattractant results in rapid (within 10 s at 37°C) and selective depolymerization of the F-actin located in lamellipodia. Addition of 10 μM cytochalasin B, in the presence of chemoattractant, also resulted in rapid and selective depolymerization of lamellar F-actin. The elevated F-actin level induced by chemoattractant rapidly returns to the level present in unstimulated cells after (a) a 10-fold decrease in chemoattractant concentration; (b) the addition of 10 μM cytochalasin B; or (c) cooling to 4°C. The F-actin levels of unstimulated cells are only slightly affected by these treatments. Based on the similar effects of cytochalasin addition and chemoattractant dilution, it is likely that both treatments result in actin depolymerization from the pointed ends of filaments. Based on our results we propose that chemoattractant-stimulated polymorphonuclear leukocytes contain two distinct populations of actin filaments. The actin filaments within the lamellipodia are highly labile and in the continued presence of chemoattractant these filaments are rapidly turning over, continually polymerizing at their plus (barbed) ends, and depolymerizing at their minus ends. In contrast, the cortical F-actin filaments of both stimulated and unstimulated cells are differentially stable.
AB - Chemoattractants stimulate actin polymerization in lamellipodia of polymorphonuclear leukocytes. We find that removal of chemoattractant results in rapid (within 10 s at 37°C) and selective depolymerization of the F-actin located in lamellipodia. Addition of 10 μM cytochalasin B, in the presence of chemoattractant, also resulted in rapid and selective depolymerization of lamellar F-actin. The elevated F-actin level induced by chemoattractant rapidly returns to the level present in unstimulated cells after (a) a 10-fold decrease in chemoattractant concentration; (b) the addition of 10 μM cytochalasin B; or (c) cooling to 4°C. The F-actin levels of unstimulated cells are only slightly affected by these treatments. Based on the similar effects of cytochalasin addition and chemoattractant dilution, it is likely that both treatments result in actin depolymerization from the pointed ends of filaments. Based on our results we propose that chemoattractant-stimulated polymorphonuclear leukocytes contain two distinct populations of actin filaments. The actin filaments within the lamellipodia are highly labile and in the continued presence of chemoattractant these filaments are rapidly turning over, continually polymerizing at their plus (barbed) ends, and depolymerizing at their minus ends. In contrast, the cortical F-actin filaments of both stimulated and unstimulated cells are differentially stable.
UR - http://www.scopus.com/inward/record.url?scp=0025219721&partnerID=8YFLogxK
U2 - 10.1083/jcb.110.4.1067
DO - 10.1083/jcb.110.4.1067
M3 - Article
C2 - 2324192
AN - SCOPUS:0025219721
SN - 0021-9525
VL - 110
SP - 1067
EP - 1075
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 4
ER -