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Abl-Interactor (Abi) Regulation of BMP-Dependent Synaptic Growth through Macropinocytosis
Abl 상호작용 단백질인 Abi 에 의한 BMP 의존적 시냅스 성장 및 macropinocytosis 의 조절

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dc.contributor.advisor이승복-
dc.contributor.author김나진-
dc.date.accessioned2018-05-28T17:13:21Z-
dc.date.available2020-02-03T23:57:55Z-
dc.date.issued2018-02-
dc.identifier.other000000150721-
dc.identifier.urihttp://hdl.handle.net/10371/141158-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 자연과학대학 협동과정 유전공학전공, 2018. 2. 이승복.-
dc.description.abstractGlass bottom boat (Gbb), a bone morphogenetic protein (BMP) in Drosophila, is a key retrograde trans-synaptic signal required for normal synaptic development and function at the neuromuscular junction (NMJ). Although endocytosis appears to be a key mechanism to attenuate BMP signaling, the underlying mechanism remains elusive. Abi (Abl interactor) is a substrate adaptor protein for the Abl tyrosine kinase protein and a key component of the SCAR/WAVE protein complex, which relays signals from Rac to the Arp2/3 complex to regulate actin dynamics during macropinocytosis. Here, I provide evidence that Abi acts as a node of convergence of Abl- and Rac-mediated signaling to restrain BMP-dependent synaptic growth through macropinocytosis. Abi, Abl, and the Rac-SCAR/WAVE pathway regulate the growth of NMJ synapses via inhibition of BMP signaling. Genetic interactions indicate that Abi acts downstream of Abl and Rac to regulate synaptic growth. Gbb induces macropinocytosis in neurons and at the NMJ. Gbb-induced macropinocytosis critically depends on the Rac-SCAR/WAVE pathway and Abl-mediated phosphorylation of Abi, both of which are critical for the formation of F-actin-rich macropinocytic carriers. Importantly, macropinocytosis mediates Gbb-induced internalization of the BMP receptor Thickveins (Tkv) and is indispensable for its degradation. Finally, loss of other known regulators of macropinocytosis increases BMP signaling and synaptic growth at the NMJ. Based on these findings, I propose that Abi links Abl signaling with the Rac-SCAR/WAVE pathway to promote ligand-induced BMP receptor downregulation through macropinocytosis, thereby limiting this positive growth signal.-
dc.description.tableofcontentsI. Introduction 1
1. Transsynaptic Bone Morphogenetic Protein (BMP) Signaling at the Drosophila Neuromuscular Junction (NMJ) 1
2. Regulation of Actin Polymerization by the Rac-WAVE Complex and Abl kinase 3
3. Regulation and Formation of Macropinocytosis 5
4. The Drosophila Neuromuscular Junction (NMJ) 7
5. Rationale and Outline of the Thesis Experiments 8
II. Materials and Methods 10
1. Fly Stocks 10
2. Molecular Biology 11
3. Antibodies 14
4. Western Blotting and GST-Pull Down Assay 16
5. Immunostaining 17
6. Cell Transfection and RNA Interference 18
7. Production of Gbb-Conditioned Medium 19
8. Macropinocytosis Assay 20
9. Tkv Receptor Degradation Assay 21
10. Time-Lapse Imaging 22
11. Survival Rate Analysis 22
III. Results 23
1. Generation of the abi Null Mutant 23
2. Abi Localizes to the Periactive Zone of the NMJ 26
3. Abi Is Required Presynaptically for Normal NMJ Growth 29
4. Presynaptic Requirements for Functional Abi Domains 37
5. Abi, the WAVE Complex, and Rac1 Act Together to Regulate Synaptic Growth 42
6. Abi Acts Downstream of Abl Kinase during Synaptic Growth 46
7. Abi, Abl, and Rac1 Restrain Synaptic Growth Via Inhibition of Retrograde BMP Signaling 50
8. Abi, Abl, and Rac1 Regulate Synaptic Growth through Modulation of Microtubule Stability 53
9. Abi Interacts with Endocytic Mutants to Regulate Synaptic Growth 61
10. Gbb Induces Macropinocytosis in a Dose-Dependent Manner in Cultured Neurons 65
11. Abi, Abl and the WAVE Complex Is Required for Macropinocytosis in BG2-c2 Cells 71
12. Macropinocytosis and Maturation of Macropinosome in BG2-c2 Cells 72
13. Abi Is Involved in the Early Stages of Macropinocytosis 86
14. Abl Kinase Activity Is Necessary for Abi Targeting to Macropinocytic Structure 87
15. The Kette- and SCAR-Binding Domains of Abi are Essential for Localized Actin Polymerization at Macropinocytic Structures 91
16. BMPR Internalization via Abi-Dependent Macropinocytosis Is Indispensable for Downregulation of BMPR 94
17. Abi and BMP Signaling Is Required for Gbb-Induced Macropinocytosis at the NMJ 101
18. Rabankyrin and CtBP, Regulators of Macropinocytosis, Also Control BMP Signaling at the NMJ 107
IV. Discussion 113
VI. References 123
ABSTRACT IN KOREAN 132
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dc.formatapplication/pdf-
dc.format.extent7426818 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectMacropinocytosis-
dc.subjectSynaptic growth-
dc.subjectNMJ synapses-
dc.subjectAbi-
dc.subjectAbl-
dc.subjectRac-
dc.subjectGbb-
dc.subjectBMP receptor-
dc.subject.ddc575-
dc.titleAbl-Interactor (Abi) Regulation of BMP-Dependent Synaptic Growth through Macropinocytosis-
dc.title.alternativeAbl 상호작용 단백질인 Abi 에 의한 BMP 의존적 시냅스 성장 및 macropinocytosis 의 조절-
dc.typeThesis-
dc.description.degreeDoctor-
dc.contributor.affiliation자연과학대학 협동과정 유전공학전공-
dc.date.awarded2018-02-
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College of Natural Sciences (자연과학대학)Program in Genetic Engineering (협동과정-유전공학전공)Theses (Ph.D. / Sc.D._협동과정-유전공학전공)
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