ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract : N-Copine is a novel protein with two C2 domains.Its expression is brain specific and up-regulated by neuronal activity such askainate stimulation and tetanus stimulation evoking hippocampal CA1 long-termpotentiation. We examined the localization and subcellular distribution ofN-copine in mouse brain. In situ hybridization analysis showed thatN-copine mRNA was expressed exclusively in neurons of the hippocampusand in the main and accessory olfactory bulb, where various forms of synapticplasticity and memory formation are known to occur. In immunohistochemicalanalyses, N-copine was detected mainly in the cell bodies anddendrites in the neurons, whereas presynaptic proteins such as synaptotagmin Iand rab3A were detected in the regions where axons pass through. Infractionation experiments of brain homogenate, N-copine wasassociated with the membrane fraction in the presence of Ca2+ butnot in its absence. As a GST-fusion protein with the second C2 domain ofN-copine showed Ca2+ -dependent binding tophosphatidylserine, this domain was considered to be responsible for theCa2+ -dependent association of N-copine with the membrane.Thus, N-copine may have a role as a Ca2+ sensor in postsynaptic events, in contrast to the known roles of “double C2 domain-containing proteins,” including synaptotagmin I, in presynaptic events.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1471-4159.1999.0720373.x
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