목차

PART I 1
Ⅰ. INTRODUCTION 2
Ⅱ. MATERIALS AND METHODS 8
A. Reagents and antibodies 8
B. Cell culture and transfections 8
C. Plasmid construction 9
D. Immunocytochemistry and confocal microscopy 9
E. Immunoprecipitation and immunoblotting 10
F. In vivo ubiquitinylation assay 11
G. Death cells counting 11
Ⅲ. RESULTS 12
A. The Mfn1 level is elevated in stress-induced mitochondrial hyper-fusion (SIMH) 12
B. Mfn1 levels were regulated through poly-ubiquitylation by mitochondrial E3 ligase, MARCH5 18
C. MARCH5 regulates the expression level of Mfn1 in SIMH 25
D. MARCH5 interacts with Mfn1 tightly and enhances ubiquitylation of Mfn1 in SIMH 29
E. MARCH5 functions cellular survival against apoptosis through regulating Mfn1 36
Ⅳ. DISCUSSION 40
Ⅴ. CONCLUSION 44
PART II 45
Ⅰ. INTRODUCTION 46
Ⅱ. MATERIALS AND METHODS 49
H. Cell culture and transfections 49
I. RNA interference and plasmids 49
J. Immunocytochemistry and confocal microscopy 50
K. Analysis of cellular granularity, reactive oxygen species (ROS), mitochondrial membrane otential, and mitochondrial mass 51
L. Immunocytochemistry and confocal microscopy 52
M. Senescence-associated β-galactosidase (SA-β-gal) assay 52
Ⅲ. RESULTS 54
F. Knockdown of MARCH5 results in elongated mitochondria and cellular senescence 54
G. Expression of a RING-domain mutant of MARCH5 increases positive SA-β-Gal staining 60
H. Mfn1 is a major ubiquitination substrate of MARCH5 67
I. Introduction of Drp1 into MARCH5-depleted cells attenuates the level of SA-β-Gal staining 72
Ⅳ. DISCUSSION 76
Ⅴ. CONCLUSION 79
Ⅵ. REFERENCES 80
Ⅶ. 국문요약 93