Characterizing the Function of MON1A in Membrane Traffic and Organelle Maintenance in the Secretory Pathway

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Publication Type dissertation
School or College School of Medicine
Department Pathology
Author Bagley, Dustin C.
Title Characterizing the Function of MON1A in Membrane Traffic and Organelle Maintenance in the Secretory Pathway
Date 2013-08
Description Mon1 is an evolutionarily conserved gene that has homologs from yeast to humans. The original identification and characterization of Mon1 in mammals, Mon1a, was performed in a study that identified Mon1a as a modifier of iron homeostasis in mice. That work demonstrated that C57BL mice harbor an intrinsic "gain-of-function" mutation that resulted in an excess of the iron exporter ferroportin at the cell surface of iron recycling macrophages. The study also showed that Mon1a had a function in the movement of soluble and membrane-bound proteins through the secretory apparatus. We were able to expand on those findings using protein interaction and RNAi analysis to demonstrate that Mon1a associates with the molecular motor Dynein, known to function in ER-Golgi trafficking. Subcellular localization demonstrated that Mon1a peripherally associates with the ER membrane. Further, RNAi-mediated reduction of Mon1a resulted in a significant decrease in the formation of ER-derived vesicle, which resulted in impaired trafficking in the early secretory pathway. We also determined that the movement of the viral protein VSVGtsGFP from the Golgi to the plasma membrane was delayed in Mon1a-depleted cells. A yeast two-hybrid (Y2H) analysis of Mon1a interacting partners found that a F-BAR domain-contain protein, FCHo2, known to affect membrane traffic at the cell surface, physically associated with Mon1a. RNAi-mediate reduction of Mon1a or iv FCHo2 resulted in severe Golgi fragmentation, which was dependent on the activity of the Golgi GTPase Rab6. The RNAi-mediate phenotypes of Mon1a and FCHo2 were not identical as only FCHo2 silencing-induced Golgi fragmentation was cell cycle-dependent. We show using FRAP analysis that FCHo2 is necessary for the lateral movement of membrane proteins between Golgi elements that link Golgi cisternae. We determined that FCHo2-mediated Golgi fragmentation resulted in immature glycosylation moieties at the plasma membrane. This dissertation describes novel roles for both Mon1a and FCHo2 in membrane traffic in the secretory pathway and Golgi architecture maintenance.
Type Text
Publisher University of Utah
Subject MESH Glycosylation; Protein Transport; Endoplasmic Reticulum; Golgi Apparatus; Iron; Macrophages; Dyneins; Mice; Secretory Pathway; Cation Transport Proteins; Secretory Vesicles; HeLa Cells
Dissertation Institution University of Utah
Dissertation Name Doctor of Philosophy
Language eng
Relation is Version of Digital reproduction of Characterizing the Function of MON1A in Membrane Traffic and Organelle Maintenance in the Secretory Pathway. Spencer S. Eccles Health Sciences Library. Print version available at J. Willard Marriott Library Special Collections.
Rights Management Copyright © Dustin C. Bagley 2013
Format Medium application/pdf
Format Extent 7,725,824 bytes
Source Original in Marriott Speical Collection, QH9.7 2013.B335
ARK ark:/87278/s6q277gj
Setname ir_etd
Date Created 2014-06-26
Date Modified 2017-05-11
ID 196625
Reference URL https://collections.lib.utah.edu/ark:/87278/s6q277gj
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