Calcium gradients underlying polarization and chemotaxis of eosinophils.
The concentration of intracellular free calcium ([Ca2+]i) in polarized eosinophils was imaged during chemotaxis by monitoring fluorescence of the calcium-sensitive dye Fura-2 with a modified digital imaging microscope. Chemotactic stimuli caused [Ca2+]i to increase in a nonuniform manner that was related to cell activity. In cells moving persistently in one direction, [Ca2+]i was highest at the rear and lowest at the front of the cell. Before cells turned, [Ca2+]i transiently increased. The region of the cell that became the new leading edge had the lowest [Ca2+]i. These changes in [Ca2+]i provide a basis for understanding the organization and local activity of cytoskeletal proteins thought to underlie the directed migration of many cells.
Brundage
R A
RA
Department of Physiology, University of Massachusetts Medical School, Worcester 01605.
Fogarty
K E
KE
Tuft
R A
RA
Fay
F S
FS
D002118:Calcium / Q000097:blood*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D004804:Eosinophils / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D016257:Fura-2; D006801:Humans; D066298:In Vitro Techniques; D015759:Ionomycin / Q000494:pharmacology; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods; D008858:Microscopy, Phase-Contrast / Q000295:instrumentation / Q000379:methods
D015759:Ionomycin; D002118:Calcium; D016257:Fura-2