Divergent evolution of di-lysine ER retention vs. farnesylation motif-mediated anchoring of the ankb PDF
Preview Divergent evolution of di-lysine ER retention vs. farnesylation motif-mediated anchoring of the ankb
UUnniivveerrssiittyy ooff LLoouuiissvviillllee TThhiinnkkIIRR:: TThhee UUnniivveerrssiittyy ooff LLoouuiissvviillllee''ss IInnssttiittuuttiioonnaall RReeppoossiittoorryy Electronic Theses and Dissertations 5-2018 DDiivveerrggeenntt eevvoolluuttiioonn ooff ddii--llyyssiinnee EERR rreetteennttiioonn vvss.. ffaarrnneessyyllaattiioonn mmoottiiff--mmeeddiiaatteedd aanncchhoorriinngg ooff tthhee aannkkbb vviirruulleennccee eeffffeeccttoorr.. John David Perpich University of Louisville Follow this and additional works at: https://ir.library.louisville.edu/etd Part of the Life Sciences Commons, and the Medicine and Health Sciences Commons RReeccoommmmeennddeedd CCiittaattiioonn Perpich, John David, "Divergent evolution of di-lysine ER retention vs. farnesylation motif-mediated anchoring of the ankb virulence effector." (2018). Electronic Theses and Dissertations. Paper 2978. https://doi.org/10.18297/etd/2978 This Doctoral Dissertation is brought to you for free and open access by ThinkIR: The University of Louisville's Institutional Repository. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of ThinkIR: The University of Louisville's Institutional Repository. This title appears here courtesy of the author, who has retained all other copyrights. For more information, please contact [email protected]. DIVERGENT EVOLUTION OF DI-LYSINE ER RETENTION VS. FARNESYLATION MOTIF-MEDIATED ANCHORING OF THE ANKB VIRULENCE EFFECTOR By John David Perpich B.S., Michigan State University, 1999 M.S., Michigan State University, 2001 Pharm.D., Medical University of South Carolina, 2007 A Dissertation Submitted to the Faculty of the School of Medicine of the University of Louisville in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Microbiology and Immunology Department of Microbiology and Immunology University of Louisville Louisville, KY May 2018 Copyright 2018 by John David Perpich All rights reserved DIVERGENT EVOLUTION OF DI-LYSINE ER RETENTION VS. FARNESYLATION MOTIF-MEDIATED ANCHORING OF THE ANKB VIRULENCE EFFECTOR By John David Perpich B.S., Michigan State University, 1999 M.S., Michigan State University, 2001 Pharm.D., Medical University of South Carolina, 2007 A Dissertation Approved on April 12, 2018 by the following Dissertation Committee: ___________________________________ Dissertation Director Dr. Yousef Abu Kwaik ___________________________________ Dr. Donald Demuth ___________________________________ Dr. Matthew Lawrenz ___________________________________ Dr. Jonathan Warawa ___________________________________ Dr. Michael Merchant ii DEDICATION To my wife, Amy, for her willingness to support me in this endevour and in the next phase of my career. For staying by my side during our most difficult times. To my son, Ethan, for always putting a smile on my face and teaching me to always be positive. I love them both more than words can express. iii ACKNOWLEDGMENTS I thank my mentor, Yousef Abu Kwaik, for always being available and willing to guide me and for helping me find my faults and grow beyond them. Also for his many pieces of valuable advice. I also thank my committee for their guidance. In particular, Dr. Michael Merchant for many hours of troubleshooting as well as career guidance. I am grateful to Dr. Michele Kosiewicz for all her time and invaluable advice on my career. iv ABSTRACT DIVERGENT EVOLUTION OF DI-LYSINE ER RETENTION VS. FARNESYLATION MOTIF-MEDIATED ANCHORING OF THE ANKB VIRULENCE EFFECTOR John Perpich April 12, 2018 Legionella pneumophila is an aquatic organism capable of intracellular replication within a wide range of protozoan hosts and within human macrophages where it causes Legionnaires’ Disease. L. pneumophila manipulates a variety of host cell processes by translocating, into the host cell cytosol, more than 300 effector proteins via the type IVB secretion system (T4SS). The AnkB effector from the AA100/130b strain (AnkB-AA100) contains a C-terminal CaaX motif that rapidly becomes farnesylated upon translocation into the host cell and anchored to the cytosolic face of the Legionella-containing vacuole (LCV) membrane, which is essential for intracellular replication. We show that a homolog of AnkB from the Paris strain (AnkB-Paris) has a frameshift mutation that truncates the C-terminus eliminating the CaaX motif, but creating a unique KNKYAP sequence that resembles a eukaryotic di-lysine ER retention motif (KxKxx). AnkB-Paris localizes to the cytosolic face of the LCV membrane most likely through the ER retention motif. Phylogenetic analyses indicate that the AnkB-Paris allele is common among environmental isolates and is positively v selected specifically for the di-lysine motif. Ectopic expression of AnkB-Paris results in a perinuclear distribution and trans-rescues the ankB mutant of the AA100/130b strain for intravacuolar replication. The trans-rescue is dependent on an intact di-lysine ER-retention motif, which most likely enables anchoring of AnkB to the ER-derived LCV membrane. AnkB contains a N-terminal eukaryotic F-box domain that recruits the cellular ubiquitylation machinery by interacting with the host Skp1 protein resulting in decoration of the LCV with polyubiquitylated proteins. Proteins targeted for ubiquitylation during infection are likely bound by ankyrin domains in the C-terminus of AnkB. Based on the crystal structure, we identified four residues within the ankyrin domains likely involved in binding specific substrate proteins. Mutation of these residues did not affect protein folding but resulted in loss of accumulation of ubiquitylated proteins around the LCV and a severe defect in intracellular replication, similar to the ankB null mutant. Overall, we identified a di-lysine ER retention motif in the C- terminus of AnkB-Paris and 4 substrate binding residues within the 3 ankyrin domains of AnkB-AA100 both of which are essential for biological function. vi TABLE OF CONTENTS PAGE DEDICATION…………………………………………………………………………iii ACKNOWLEDGEMENTS…………………………………………………………...iv ABSTRACT……………………………………………………………………………v LIST OF TABLES…………………………………………………………………….ix LIST OF FIGURES…………………………………………………………………..xi INTRODUCTION……………………………………………………………………...1 I. History and Etiology of Legionnaires’ Disease………………………...1 II. Epidemiology and Clinical Manifestations……………………………...2 III. Microbial Ecology and Transmission.…………………………………...5 IV. Metabolism…………………………………………………………………6 V. Intracellular Life Cycle…………………………………………………….8 VI. T4SS and Manipulation of Host Cell Processes……………………….8 VII. Genome Plasticity………………………………………………………..10 VIII. Ankyrin Domain-Containing Proteins in L. pneumophila…………….14 IX. Protein Ubiquitylation…………………………………………………….15 X. Manipulation of Host Ubiquitylation Pathways………………………...18 XI. Manipulation of Host Prenylation……………………………………….20 XII. AnkB……………………………………………………………………….22 SPECIFIC AIMS………………………………………………………………………27 MATERIALS AND METHODS………………………………………………………29 CHAPTER 1: Identification of Host Protein Targets of AnkB……………………41 I. Results……………………………………………………………………..41 In vitro Pull Down………………………………………………………….41 Identification of AnkB Substrates by Two-Step Immunoprecipitation..48 AnkB Substrate Identification by Formaldehyde Cross-Linking………53 II. Discussion………………………………………………………………….56 vii
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