High micromolar Ca2+ beneath the plasma membrane in stimulated neutrophils.
Ca2+ near the inner face of the plasma membrane, as reported by the membrane associated fluorescent Ca2+ probe FFP-18, was higher than the bulk cytosolic free Ca2+ concentration both in resting neutrophils and in response to f-met-leu-phe. Influx caused Ca2+ close to the plasma membrane to rise more rapidly than the bulk cytosolic free Ca2+ and to reach a peak concentration of at least 30 microM. This zone of high Ca2+ was localised to just beneath the plasma membrane and did not extend more than 0.1 micron into the cell, as it was undetected by the bulk cytosolic free Ca2+ probes magfura2 and fura2. From these data, reconstruction of the distribution of Ca2+ within the neutrophil showed that the high Ca2+ signal at the cell cortex rapidly subsided to give a uniform free Ca2+ across the cell.
Davies
E V
EV
University Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff, United Kingdom.
Hallett
M B
MB
D002118:Calcium / Q000097:blood*; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013997:Time Factors
D005456:Fluorescent Dyes; C098105:fura-FFP18; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002118:Calcium; D016257:Fura-2