RT Journal Article
SR Electronic
T1 Involvement of Protein Kinase C-ε in Activity-Dependent Potentiation of Large Dense-Core Vesicle Exocytosis in Chromaffin Cells
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 8999
OP 9005
DO 10.1523/JNEUROSCI.2828-06.2006
VO 26
IS 35
A1 Yong-Soo Park
A1 Eun-Mi Hur
A1 Bo-Hwa Choi
A1 Eunyee Kwak
A1 Dong-Jae Jun
A1 Su-Jin Park
A1 Kyong-Tai Kim
YR 2006
UL http://www.jneurosci.org/content/26/35/8999.abstract
AB Neurotransmitter release is modulated in an activity-dependent manner. We showed previously that repetitive stimulation of nicotinic acetylcholine receptor (nAChR) induced activity-dependent potentiation (ADP) of large dense-core vesicle (LDCV) exocytosis in chromaffin cells. Here we report that protein kinase C (PKC)-ε is critically involved in ADP. Stimulation of nAChR induced activation of PKC-ε, and inhibition of PKC-ε by expression of the dominant-negative mutant of PKC-ε (DN-PKC-ε) or short interfering (siRNA) against PKC-ε abolished ADP via decreasing the frequency and quantal size of fused vesicles without affecting basal exocytosis, suggesting that PKC-ε is specifically involved in ADP. Electron microscopy revealed that inhibition of PKC-ε disrupts activity-induced vesicle translocation required for ADP. We also suggest the involvement of myristoylated alanine-rich C kinase substrate (MARCKS), which is known as a downstream target of PKC-ε, in ADP of LDCV exocytosis. The level of phospho-MARCKS correlated with the time course of ADP and was reduced by transfection with DN-PKC-ε. Actin filament disassembly induced by MARCKS phosphorylation was also significantly blocked by transfection of DN-PKC-ε. Furthermore, knockdown of MARCKS by siRNA resulted in inhibition of ADP and reduction of the number of fused vesicles. Together, we provide evidence that ADP of LDCV exocytosis is regulated by PKC-ε and its downstream target MARCKS via modulating vesicle translocation.