Signaling to localized degranulation in neutrophils adherent to immune complexes.
The present study demonstrates that the secretion of azurophilic granules occurring during Fc receptor-mediated attachment and spreading of neutrophils is highly localized to the adhering region of the cell. In contrast, the secretion of specific granules occurs in a nonpolarized way. This implies that unique signals are involved in the regulation of azurophilic degranulation. Assembly of actin filaments, as visualized by staining with rhodamine phalloidin, neither hindered nor facilitated degranulation. Further, the azurophilic secretory response remained localized in the presence of cytochalasin B. Release of azurophilic-granule content was inhibited by genistein and erbstatin, inhibitors of tyrosine kinases, and by GF109203X, a protein kinase C (PKC) inhibitor. We could also demonstrate a relative enrichment of syk tyrosine kinase and the PKC isoforms alpha and beta1 in adherent plasma membranes.
Nauclér
Claes
C
Department of Cell and Molecular Biology, BMC, Lund University, Sweden.
Grinstein
Sergio
S
Sundler
Roger
R
Tapper
Hans
H
D000199:Actins / Q000378:metabolism; D000936:Antigen-Antibody Complex / Q000502:physiology*; D002448:Cell Adhesion; D015550:Cell Degranulation; D003571:Cytochalasin B / Q000494:pharmacology; D004792:Enzyme Precursors / Q000032:analysis; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes / Q000032:analysis; D009504:Neutrophils / Q000502:physiology*; D011493:Protein Kinase C / Q000032:analysis / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000502:physiology; D000072377:Syk Kinase
D000199:Actins; D000936:Antigen-Antibody Complex; D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes; D003571:Cytochalasin B; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; D011493:Protein Kinase C