Articles

Article

Original

Exp Neurobiol 2004; 13(2): 111-118

Published online December 31, 2004

© The Korean Society for Brain and Neural Sciences

Puncta Expression and Regulation of Myristoylated Alanine-rich C Kinase Substrate (MARCKS) in the Mossy Fiber Pathways of Adult Mouse Hippocampus

Eun Hae Kim1, Hwa Jung Kim1, Kee-Seok Kang1,Sangmee Ahn Jo1, Jun Kim2 and Su-Yong Eun1*

1Division of Brain Diseases and Biomedical Brain Research Center,Department of Biomedical Sciences, National Institute of Health, Seoul 122-701,Korea, 2Department of Physiology and Biophysics, Seoul National University,College of Medicine, Seoul 110-799, Korea

Correspondence to: *To whom correspondence should be addressed.
TEL: 82-2-380-1527, FAX: 82-2-354-1057
e-mail: suyong1@nih.go.kr

Abstract

Myristoylated alanine-rich C kinase substrate (MARCKS) has been implicated in neu-rotransmitter release and synaptic plasticity associated with actin cytoskeletal rear-rangement. However, the precise expression pattern was not investigated yet regarding these issues. Therefore, we examined here the expression and alteration of regional and cellular distribution of MARCKS protein in the hippocampus before and after KA-induced seizures, as one of in vivo activity-dependent neural plasticity models. Eight to nine week old C57BL/6 mice were administered with kainic acid (KA, 25 mg/kg, i.p.) and behavioral seizure activities were observed. Animals were fixed 4 h, 1 d, 4 d, 1 week, 2 weeks and 1 month after KA injection and processed for immunohisto-chemistry. We demonstrated here that neuronal expression of MARCKS seems to be only confined to small puncta structures such as axon terminal in the hippocampus. These MARCKS immunoreactive (IR) puncta were sharply demarcated in dentate hilus and stratum lucidum where mossy fibers of dentate gyrus granule cells are terminated and form excitatory synapses with CA3 pyramidal cells. The total protein expression of MARCKS was not altered in these hippocampal structures following KA-induced seizures. However, MARCKS phosphorylation was markedly increased. These findings suggest that MARCKS might contribute to regulate neurotransmitter release, axonal sprouting and synaptic reorganization in mossy fiber pathways following seizure activities.

Keywords: MARCKS, PKC, mossy fiber, hippocampus, gene expression, seizure