Roles of ERK1/2 signaling in LMNA‐cardiomyopathy A Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of “Doctor rerum naturalium (Dr. rer. nat.)” to the Department of Biology, Chemistry and Pharmacy of Freie Universität Berlin by Maria Chatzifrangkeskou Berlin, 2016 Supervisor: Prof. Petra Knaus Second examiner: Prof. Sigmar Stricker Date of the defense: 08/11/2016 Table of Contents Chapter 1 Introduction ................................................................................................................. 14 1.1 Nucleus, nuclear lamina and laminopathies ....................................................................... 14 1.1.1 Nuclear lamins .............................................................................................................. 15 1.1.2 Structure of lamins ....................................................................................................... 18 1.1.3 Posttranslational Processing and Modifications of the Nuclear Lamins ...................... 19 1.1.4 Lamin filament assembly and disassembly .................................................................. 19 1.1.5 Connections of A‐type lamins with other nuclear envelope proteins ......................... 20 1.1.6 Connections between nucleus and cytoskeleton ......................................................... 22 1.1.7 Laminopathies .............................................................................................................. 27 1.1.8 Pathophysiology ........................................................................................................... 33 1.1.9 Animal models .............................................................................................................. 34 1.1.10 Current therapeutic options for striated muscle laminopathies ............................... 37 1.1.11 Potential new treamtents........................................................................................... 37 1.1.12 Other therapeutic options .......................................................................................... 40 1.2 Actin..................................................................................................................................... 42 1.2.1 Nucleator proteins ........................................................................................................ 43 1.2.2 Profilin........................................................................................................................... 46 1.2.3 Capping protein (CP) ..................................................................................................... 47 1.2.4 Severing proteins .......................................................................................................... 47 1.2.5 Actin filaments in muscle ............................................................................................. 53 1.2.6 Regulation of sarcomeric actin filaments ..................................................................... 55 1.3 TGF‐β (Transforming growth factor‐β) superfamily signaling ............................................ 59 1.3.1 Non‐Smad signaling pathways ..................................................................................... 63 1.3.2 Role of TGF‐β in diseases .............................................................................................. 64 1.3.3 TGF‐β in fibrosis ............................................................................................................ 65 1.3.4 TGF‐β‐induction of connective tissue growth factor ................................................... 68 Chapter 2 Manuscripts .................................................................................................................. 71 Chapter 3 Discussion ................................................................................................................... 136 Chapter 4 Bibliography ............................................................................................................... 151 Chapter 5 Appendices ................................................................................................................. 175 5.1 Appendix I .......................................................................................................................... 176 5.2 Appendix II ......................................................................................................................... 181 Chapter 6 Acknowledgments ...................................................................................................... 188 4 | Page Table of figures Figure 1: The eukaryotic nucleus ……………………………………………………………………………………………….…………13 Figure 2: Schematic structure of lamin family members……………………………………………………………….………18 Figure 3: Schematic illustration of the LEM‐domain proteins……………………………………………………….………21 Figure 4: Schematic diagram of the nucleocytoskeleton interactions ………………………………………………....23 Figure 5: Domain structure of the four main nesprin isoforms……………………………………………………….…….24 Figure 6: Schematic representation of the two perinuclear actin structures: actin cap and TAN lines….27 Figure 7: Laminopathies affecting striated muscles……………………………………………………………………………...30 Figure 8: Morphological changes οf the heart in cardiomyopathy………………………………………………………..31 Figure 9: A simplified overview of MAPK pathways in mammals……………………………………………………..…...39 Figure 10: Schematic representation of the actin‐binding proteins (ABPs) that influence the actin treadmilling……………………………………………………………………………………………………………………………………………43 Figure 11: Arp2/3‐mediated actin nucleation………………………………………………………………………………..…….…44 Figure 12: Actin nucleation and elongation by the formin family proteins……………………………………….….…46 Figure 13: Actin nucleation by tandem monomer‐binding nucleators…………………………………………….……..46 Figure 14: Regulation of actin filament dynamics by ADF/cofilin, profiling, CAP, twinfilin and AIP1.……….49 Figure 15: Schematic overview of the ADF/cofilin kinases and phosphatases and their upstream regulators…………………………………………………………………………………………………………………………………………...….52 Figure 16: Schematic drawing of sarcomere structure and sarcomere‐binding proteins………………….….…54 Figure 17: Domains of tropomodulin (Tmod) and leiomodin (Lmod) proteins…………………………………..……57 Figure 18: Functional domains of the three Smads subfamilies ………………………………………………………..……60 Figure 19: Schematic illustration of myofibroblast transdifferentiation.......................................................61 Figure 20: Schematic representation of the TGF‐β signaling pathway …………………………..……………………....66 Figure 21: The TGF–TAK1 pathway………………………………………………………………………………….…………….……..…68 Figure 22: Hypothetical model of increased TGF‐β signaling LmnaH222P/H222P mice……………….………….…….138 Figure 23: MRTF‐SRF axis………………………………………………………………………………………………………….……………144 Figure 24: Models of how abnormalities of A‐type lamins may lead to hyperactivation of ERK1/2…... ..146 Figure 25: Schematic representation of the data obtained during this thesis. ………………………………….……148 5 | Page Abbreviations ACE, angiotensin II converting enzyme EDMD, Emery Dreifuss muscular dystrophy ADF, actin-depolymerizing factor EF, ejection fraction ALK, activin receptor-like kinases ERK, extracellular sign-regulated kinases ALS, amyotrophic lateral sclerosis ERK1/2 extracellular signal-regulated kinase 1/2 AMH/MIS, anti-Müllerian hormone/Müllerian ESCs, embryonic stem cells inhibiting substance F-actin, filamentous actin AP-1 activator protein-1 FAK, focal adhesion kinase ATF-2, activated transcription factor-2 FH1, formin-homology 1; aWRN, atypical Werner syndrome FH2, formin-homology 2 BAF, Barrier to Autointegration Factor FPLD, familial lipodystrophy of Dunnigan type BMP, bone-morphogenetic protein FR, fractional shortening CaMKII, Ca2+/calmodulin-dependent protein FRAP, fluorescence-recovery after photobleaching kinase II, FS, Fractional shortening CBD, chromatin binding domain G-actin, globular actin Cdc42, cell division cycle 42, GDF, growth and differentiation factors family CDK, cyclin dependent kinases GPCR, G-protein-coupled receptors Cdk1, cyclin dependent kinase-1 GSK, Glycogen synthase kinase 3 CH, Calponin-homology domain HGPS, Hutchinson-Gilford progeria syndrome CIN, chronophin HP1, heterochromatin-associated protein-1 CMD, Congenital muscular dystrophy ICD, intracardiac cardioverter defibrillator CMT2B1, Charcot-Marie Tooth type 2B1 ICMT, isoprenylcysteine carboxyl Cobl, cordon-bleu methyltransferase Co-Smads, common Smads, INM, inner nuclear membrane CP, capping protein iPSCs, induced pluripotent stem cells CTGF, Connective Tissue Growth Factor I-Smads, inhibitory Smads, DAG, diaglycerol JNK, c-Jun N terminal kinase DCM, dilated cardiomyopathy JNK, c-JUN N-terminal kinase DCM-CD, dilated cardiomyopathy with KASH, Klarsicht/ANC-1/Syne-1 homologue conduction system disease LAD, lamina-associated domains ECG, electrocardiogram LAP, lamina-associated polypeptide ECM, extracellular matrix LAP, latency-associated peptide 6 | Page LBR, lamin B receptor PP1, protein phosphatase 1 LEM, Lamina-associated polypeptide, Emerin PP2A, protein phosphatase 2A and-MAN1 Rce1, Ras-converting enzyme 1 LGMD1B, limb-girdle muscular dystrophy type ROCK, RHO-associated coiled-coil-containing 1B protein kinase LIMK, Lin-11/Isl-1/Mec-3 kinase R-Smads, regulatory Smads LINC, LInker of Nucleoskeleton and RTK, receptor tyrosine kinase Cytoskeleton RTK, receptors with intrinsic tyrosine kinase Lmod, leiomodin activity LV, left ventricule