목차

ABSTRACT i
TABLE OF CONTENTS iii
LIST OF FIGURES vi
ABBREVIATION viii
I. INTRODUCTION 1
A. Cadherins in nervous system. 1
B. Involvement of proteases on N-cadherin cleavage. 3
C. Calpain activation in pathological conditions 5
D. Aims of study 7
1. Involvement of calpain on N-cadherin cleavage 7
2. Physiological consequences of calpain-mediated N-cadherin cleavage. 8
II. MATERIALS AND METHODS 9
A. Materials 9
B. Cell culture 10
1. Pure cortical neurons 10
2. Astrocytes 10
C. Treatment 10
D. In vitro calpain assay 11
E. DNA constructs and transfection 11
F. Western blot analysis 12
G. Subcellular fractionation 13
H. Biotinylation assay 14
I. Immunoprecipitation (IP) 14
J. Immunofluorescence 14
K. Focal cerebral ischemia in vivo model 15
L. Cell dissociation assay 16
M. RT-PCR (Reverse Transcription-Polymerase Chain Reaction) 16
N. Measurement of cell viability 17
O. Statistical analysis 17
III. RESULTS 18
A. NMDA receptor-induced calcium influx increases N-cadherin cleavage. 18
B. Calpain is responsible for N-cadherin cleavage. 22
C. Calpain cleaves intracellular domain of N-cadherin. 29
D. Calpain is responsible for N-cadherin cleavage in ischemic brain injury. 32
E. Identification of the N-cadherin cleavage sites. 36
F. Calpain-mediated cleavage fragments are degraded by proteasome system. 40
G. Alterations of surface N-cadherin expression and N-cadherin/β-catenin interaction
by calpain after NMDA stimulation. 43
H. Nuclear β-catenin accumulation after calpain inhibition induces the expression of
Wnt target genes. 48
I. Expression and cleavage of N-cadherin regulates directly AKT signaling. 51
J. Calpain-mediated N-cadherin cleavage inhibits cell-cell adhesion. 53
IV. DISCUSSION 58
REFERENCES 63
국문요약 79