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F-actin and myosin II accelerate catecholamine release from chromaffin granules.

ABSTRACT: The roles of nonmuscle myosin II and cortical actin filaments in chromaffin granule exocytosis were studied by confocal fluorescence microscopy, amperometry, and cell-attached capacitance measurements. Fluorescence imaging indicated decreased mobility of granules near the plasma membrane following inhibition of myosin II function with blebbistatin. Slower fusion pore expansion rates and longer fusion pore lifetimes were observed after inhibition of actin polymerization using cytochalasin D. Amperometric recordings revealed increased amperometric spike half-widths without change in quantal size after either myosin II inhibition or actin disruption. These results suggest that actin and myosin II facilitate release from individual chromaffin granules by accelerating dissociation of catecholamines from the intragranular matrix possibly through generation of mechanical forces.

SUBMITTER: Berberian K

PROVIDER: S-EPMC2768403 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature

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F-actin and myosin II accelerate catecholamine release from chromaffin granules.

Berberian Khajak K Torres Alexis J AJ Fang Qinghua Q Kisler Kassandra K Lindau Manfred M

The Journal of neuroscience : the official journal of the Society for Neuroscience 20090101 3

The roles of nonmuscle myosin II and cortical actin filaments in chromaffin granule exocytosis were studied by confocal fluorescence microscopy, amperometry, and cell-attached capacitance measurements. Fluorescence imaging indicated decreased mobility of granules near the plasma membrane following inhibition of myosin II function with blebbistatin. Slower fusion pore expansion rates and longer fusion pore lifetimes were observed after inhibition of actin polymerization using cytochalasin D. Ampe ...[more]

PMID: 19158310

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