Search

Publisher's version (útgefin grein)., Background: Genome-wide association studies conducted on QRS duration, an electrocardiographic measurement associated with heart failure and sudden cardiac death, have led to novel biological insights into cardiac function. However, the variants identified fall predominantly in non-coding regions and their underlying mechanisms remain unclear. Results: Here, we identify putative functional coding variation associated with changes in the QRS interval duration by combining Illumina HumanExome BeadChip genotype data from 77,898 participants of European ancestry and 7695 of African descent in our discovery cohort, followed by replication in 111,874 individuals of European ancestry from the UK Biobank and deCODE cohorts. We identify ten novel loci, seven within coding regions, including ADAMTS6, significantly associated with QRS duration in gene-based analyses. ADAMTS6 encodes a secreted metalloprotease of currently unknown function. In vitro validation analysis shows that the QRS-associated variants lead to impaired ADAMTS6 secretion and loss-of function analysis in mice demonstrates a previously unappreciated role for ADAMTS6 in connexin 43 gap junction expression, which is essential for myocardial conduction. Conclusions: Our approach identifies novel coding and non-coding variants underlying ventricular depolarization and provides a possible mechanism for the ADAMTS6-associated conduction changes., Funding This work was funded by a grant to YJ from the British Heart Foundation (PG/12/38/29615). AGES: This study has been funded by NIH contracts N01-AG-1-2100 and 271201200022C, the NIA Intramural Research Program, Hjartavernd (the Icelandic Heart Association), and the Althingi (the Icelandic Parliament). The study is approved by the Icelandic National Bioethics Committee, VSN: 00–063. The researchers are indebted to the participants for their willingness to participate in the study. ARIC: The Atherosclerosis Risk in Communities Study is carried out as a collaborative study supported by National Heart, Lung, and Blood Institute contracts (HHSN268201100005C, HHSN268201100006C, HHSN268201100007C, HHSN268201100008C, HHSN268201100009C, HHSN268201100010C, HHSN268201100011C, and HHSN268201100012C), R01HL087641, R01HL59367, and R01HL086694; National Human Genome Research Institute contract U01HG004402; and National Institutes of Health contract HHSN268200625226C. The authors thank the staff and participants of the ARIC study for their important contributions. Infrastructure was partly supported by Grant Number UL1RR025005, a component of the National Institutes of Health and NIH Roadmap for Medical Research. Funding support for “Building on GWAS for NHLBI-diseases: the U.S. CHARGE consortium” was provided by the NIH through the American Recovery and Reinvestment Act of 2009 (ARRA) (5RC2HL102419). BRIGHT: The Exome Chip genotyping was funded by Wellcome Trust Strategic Awards (083948 and 085475). This work was also supported by the Medical Research Council of Great Britain (Grant no. G9521010D); and by the British Heart Foundation (Grant no. PG/02/128). AFD was supported by the British Heart Foundation (Grant nos. RG/07/005/23633 and SP/08/005/25115); and by the European Union Ingenious HyperCare Consortium: Integrated Genomics, Clinical Research, and Care in Hypertension (grant no. LSHM-C7–2006-037093). The BRIGHT study is extremely grateful to all the patients who participated in the study and the BRIGHT nursing team. We would also like to thank the Barts Genome Centre staff for their assistance with this project. CHS: This Cardiovascular Health Study (CHS) research was supported by NHLBI contracts HHSN268201800001C, HHSN268201200036C, HHSN268200800007C, N01HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, N01HC85086; and NHLBI grants R01HL068986, U01HL080295, R01HL087652, R01HL105756, R01HL103612, R01HL120393, and U01HL130114 with additional contribution from the National Institute of Neurological Disorders and Stroke (NINDS). Additional support was provided through R01AG023629 from the National Institute on Aging (NIA). A full list of principal CHS investigators and institutions can be found at CHS-NHLBI.org. The provision of genotyping data was supported in part by the National Center for Advancing Translational Sciences, CTSI grant UL1TR001881, and the National Institute of Diabetes and Digestive and Kidney Disease Diabetes Research Center (DRC) grant DK063491 to the Southern California Diabetes Endocrinology Research Center. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. ERF: The ERF study as a part of EUROSPAN (European Special Populations Research Network) was supported by European Commission FP6 STRP grant number 018947 (LSHG-CT-2006-01947) and also received funding from the European Community’s Seventh Framework Programme (FP7/2007–2013)/grant agreement HEALTH-F4–2007-201413 by the European Commission under the programme “Quality of Life and Management of the Living Resources” of 5th Framework Programme (no. QLG2-CT-2002-01254). The ERF study was further supported by ENGAGE consortium and CMSB. High-throughput analysis of the ERF data was supported by joint grant from Netherlands Organization for Scientific Research and the Russian Foundation for Basic Research (NWO-RFBR 047.017.043). We are grateful to all study participants and their relatives, general practitioners, and neurologists for their contributions to the ERF study and to P Veraart for her help in genealogy, J Vergeer for the supervision of the laboratory work, and P Snijders for his help in data collection. FHS: The Framingham Heart Study (FHS) research reported in this article was supported by a grant from the National Heart, Lung, and Blood Institute (NHLBI), HL120393. Generation Scotland: Generation Scotland received core support from the Chief Scientist Office of the Scottish Government Health Directorates (CZD/16/6) and the Scottish Funding Council (HR03006). Genotyping of the Generation Scotland and Scottish Family Health Study samples was carried out by the Genetics Core Laboratory at the Clinical Research Facility, Edinburgh, Scotland and was funded by the UK’s Medical Research Council. GOCHA: The Genetics of Cerebral Hemorrhage with Anticoagulation was carried out as a collaborative study supported by grants R01NS073344, R01NS059727, and 5K23NS059774 from the NIH–National Institute of Neurological Disorders and Stroke (NIH-NINDS). GRAPHIC: The GRAPHIC Study was funded by the British Heart Foundation (BHF/RG/2000004). NJS and CPN are supported by the British Heart Foundation and is a NIHR Senior Investigator. This work falls under the portfolio of research supported by the NIHR Leicester Cardiovascular Biomedical Research. INGI-FVG: This study has been funded by Regione FVG (L.26.2008). INTER99: The Inter99 was initiated by Torben Jørgensen (PI), Knut Borch-Johnsen (co-PI), Hans Ibsen and Troels F. Thomsen. The steering committee comprises the former two and Charlotta Pisinger. The study was financially supported by research grants from the Danish Research Council, the Danish Centre for Health Technology Assessment, Novo Nordisk Inc., Research Foundation of Copenhagen County, Ministry of Internal Affairs and Health, the Danish Heart Foundation, the Danish Pharmaceutical Association, the Augustinus Foundation, the Ib Henriksen Foundation, the Becket Foundation, and the Danish Diabetes Association. The Novo Nordisk Foundation Center for Basic Metabolic Research is an independent Research Center at the University of Copenhagen partially funded by an unrestricted donation from the Novo Nordisk Foundation (www.metabol.ku.dk). JHS: We thank the Jackson Heart Study (JHS) participants and staff for their contributions to this work. The JHS is supported by contracts HHSN268201300046C, HHSN268201300047C, HHSN268201300048C, HHSN268201300049C, HHSN268201300050C from the National Heart, Lung, and Blood Institute and the National Institute on Minority Health and Health Disparities. Dr. Wilson is supported by U54GM115428 from the National Institute of General Medical Sciences. KORA: The KORA study was initiated and financed by the Helmholtz Zentrum München – German Research Center for Environmental Health, which is funded by the German Federal Ministry of Education and Research (BMBF) and by the State of Bavaria. Furthermore, KORA research was supported within the Munich Center of Health Sciences (MC-Health), Ludwig-Maximilians-Universität, as part of LMUinnovativ. Korcula: This work was funded by the Medical Research Council UK, The Croatian Ministry of Science, Education and Sports (grant 216–1080315-0302), the Croatian Science Foundation (grant 8875), the Centre of Excellence in Personalized health care, and the Centre of Competencies for Integrative Treatment, Prevention and Rehabilitation using TMS. LifeLines: The LifeLines Cohort Study and generation and management of GWAS genotype data for the LifeLines Cohort Study are supported by The Netherlands Organization of Scientific Research NWO (grant 175.010.2007.006), the Economic Structure Enhancing Fund (FES) of the Dutch government, the Ministry of Economic Affairs, the Ministry of Education, Culture and Science, the Ministry for Health, Welfare and Sports, the Northern Netherlands Collaboration of Provinces (SNN), the Province of Groningen, University Medical Center Groningen, the University of Groningen, Dutch Kidney Foundation, and Dutch Diabetes Research Foundation. Niek Verweij is supported by NWO-VENI (016.186.125) and Marie Sklodowska-Curie GF (call: H2020-MSCA-IF-2014, Project ID: 661395). UHP: Folkert W. Asselbergs is supported by UCL Hospitals NIHR Biomedical Research Centre. Ilonca Vaartjes is supported by a Dutch Heart Foundation grant DHF project “Facts and Figures.” MGH-CAMP: Dr. Patrick Ellinor is funded by NIH grants (2R01HL092577, 1R01HL128914, R01HL104156, and K24HL105780) and American Heart Association Established Investigator Award 13EIA14220013 (Ellinor). Dr. Steve Lubitz is funded by NIH grants K23HL114724 and a Doris Duke Charitable Foundation Clinical Scientist Development Award 2014105. NEO: The authors of the NEO study thank all individuals who participated in the Netherlands Epidemiology in Obesity study, all participating general practitioners for inviting eligible participants, and all research nurses for collection of the data. We thank the NEO study group, Pat van Beelen, Petra Noordijk, and Ingeborg de Jonge for the coordination, lab, and data management of the NEO study. We also thank Arie Maan for the analyses of the electrocardiograms. The genotyping in the NEO study was supported by the Centre National de Génotypage (Paris, France), headed by Jean-Francois Deleuze. The NEO study is supported by the participating Departments, the Division and the Board of Directors of the Leiden University Medical Center, and by the Leiden University, Research Profile Area Vascular and Regenerative Medicine. Dennis Mook-Kanamori is supported by Dutch Science Organization (ZonMW-VENI Grant 916.14.023). RS-I: The generation and management of the Illumina Exome Chip v1.0 array data for the Rotterdam Study (RS-I) was executed by the Human Genotyping Facility of the Genetic Laboratory of the Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands. The Exome chip array dataset was funded by the Genetic Laboratory of the Department of Internal Medicine, Erasmus MC, from the Netherlands Genomics Initiative (NGI)/Netherlands Organization for Scientific Research (NWO)-sponsored Netherlands Consortium for Healthy Aging (NCHA; project nr. 050–060-810); the Netherlands Organization for Scientific Research (NWO; project number 184021007); and by the Rainbow Project (RP10; Netherlands Exome Chip Project) of the Biobanking and Biomolecular Research Infrastructure Netherlands (BBMRI-NL; www.bbmri.nl). We thank Ms. Mila Jhamai, Ms. Sarah Higgins, and Mr. Marijn Verkerk for their help in creating the exome chip database, and Carolina Medina-Gomez, MSc, Lennard Karsten, MSc, and Linda Broer PhD for QC and variant calling. Variants were called using the best practice protocol developed by Grove et al. as part of the CHARGE consortium exome chip central calling effort. The Rotterdam Study is funded by Erasmus Medical Center and Erasmus University, Rotterdam, Netherlands Organization for the Health Research and Development (ZonMw), the Research Institute for Diseases in the Elderly (RIDE), the Ministry of Education, Culture and Science, the Ministry for Health, Welfare and Sports, the European Commission (DG XII), and the Municipality of Rotterdam. The authors are grateful to the study participants, the staff from the Rotterdam Study, and the participating general practitioners and pharmacists. The work of Bruno H. Stricker is supported by grants from the Netherlands Organization for Health Research and Development (ZonMw) (Priority Medicines Elderly 113102005 to ME and DoelmatigheidsOnderzoek 80–82500–98-10208 to BHS). The work of Mark Eijgelsheim is supported by grants from the Netherlands Organization for Health Research and Development (ZonMw) (Priority Medicines Elderly 113102005 to ME and DoelmatigheidsOnderzoek 80–82500–98-10208 to BHS). SHIP: SHIP is supported by the BMBF (grants 01ZZ9603, 01ZZ0103, and 01ZZ0403) and the German Research Foundation (Deutsche Forschungsgemeinschaft [DFG]; grant GR 1912/5–1). SHIP and SHIP-TREND are part of the Community Medicine Research net (CMR) of the Ernst-Moritz-Arndt University Greifswald (EMAU) which is funded by the BMBF as well as the Ministry for Education, Science and Culture and the Ministry of Labor, Equal Opportunities, and Social Affairs of the Federal State of Mecklenburg-West Pomerania. The CMR encompasses several research projects that share data from SHIP. The EMAU is a member of the Center of Knowledge Interchange (CKI) program of the Siemens AG. SNP typing of SHIP and SHIP-TREND using the Illumina Infinium HumanExome BeadChip (version v1.0) was supported by the BMBF (grant 03Z1CN22). We thank all SHIP and SHIP-TREND participants and staff members as well as the genotyping staff involved in the generation of the SNP data. TWINSUK: TwinsUK is funded by the Wellcome Trust, Medical Research Council, European Union, the National Institute for Health Research (NIHR)-funded BioResource, Clinical Research Facility and Biomedical Research Centre based at Guy’s and St Thomas’ NHS Foundation Trust in partnership with King’s College London. UKBB: This research has been conducted using the UK Biobank Resource (application 8256 - Understanding genetic influences in the response of the cardiac electrical system to exercise) and is supported by Medical Research Council grant MR/N025083/1. We also wish to acknowledge the support of the NIHR Cardiovascular Biomedical Research Unit at Barts and Queen Mary University of London, UK. PD Lambiase acknowledges support from the UCLH Biomedicine NIHR. MO is supported by an IEF 2013 Marie Curie fellowship. JR acknowledges support from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme (FP7/2007–2013) under REA grant agreement no. 608765. YFS: The Young Finns Study has been financially supported by the Academy of Finland: grants 286284, 134309 (Eye), 126925, 121584, 124282, 129378 (Salve), 117787 (Gendi), and 41071 (Skidi); the Social Insurance Institution of Finland; Competitive State Research Financing of the Expert Responsibility area of Kuopio, Tampere and Turku University Hospitals (grant X51001); Juho Vainio Foundation; Paavo Nurmi Foundation; Finnish Foundation for Cardiovascular Research; Finnish Cultural Foundation; Tampere Tuberculosis Foundation; Emil Aaltonen Foundation; Yrjö Jahnsson Foundation; Signe and Ane Gyllenberg Foundation; and Diabetes Research Foundation of Finnish Diabetes Association. The expert technical assistance in the statistical analyses by Irina Lisinen is gratefully acknowledged. Cell culture and biochemistry: Funding was provided by the National Institutes of Health (Program of Excellence in Glycoscience award HL107147 to SSA and F32AR063548 to TJM) and the David and Lindsay Morgenthaler Postdoctoral Fellowship (to TJM) and by the Allen Distinguished Investigator Program, through support made by The Paul G. Allen Frontiers Group and the American Heart Association (to SSA). Mutant mouse model: Adamts6 mutant mice were generated and further propagated and analyzed by funding provided by NIH grants HL098180 and HL132024 (to CWL) and by the Allen Distinguished Investigator Program, through support made by The Paul G. Allen Frontiers Group and the American Heart Association (to SSA).

Congenital muscular dystrophies display a wide phenotypic and genetic heterogeneity. The combination of clinical, biochemical, and molecular genetic findings must be considered to obtain the precise diagnosis and provide appropriate genetic counselling. Here we report five individuals from four families presenting with variable clinical features including muscular dystrophy with a reduction in dystroglycan glycosylation, short stature, intellectual disability, and cataracts, overlapping both the dystroglycanopathies and Marinesco-Sjogren syndrome. Whole-exome sequencing revealed homozygous missense and compound heterozygous mutations in INPP5K in the affected members of each family. INPP5K encodes the inositol polyphosphate-5-phosphatase K, also known as SKIP (skeletal muscle and kidney enriched inositol phosphatase), which is highly expressed in the brain and muscle. INPP5K localizes to both the endoplasmic reticulum and to actin ruffles in the cytoplasm. It has been shown to regulate myoblast differentiation and has also been implicated in protein processing through its interaction with the ER chaperone HSPA5/BiP. We show that morpholino-mediated inpp5k loss of function in the zebrafish results in shortened body axis, microphthalmia with disorganized lens, microcephaly, reduced touch-evoked motility, and highly disorganized myofibers. Altogether these data demonstrate that mutations in INPP5K cause a congenital muscular dystrophy syndrome with short stature, cataracts, and intellectual disability.

Introduction/Objectives In Duchenne muscular dystrophy (DMD), myofibres die with a necrotic morphology, however the cell death mechanisms are largely unknown. Inflammation plays a significant part in muscle degeneration. Necroptosis is a newly identified programmed form of necrosis, which is driven by receptor interacting protein kinase 3 (RIPK3). It plays a major role in the inflammation-induced injuries in several tissues. We are currently investigating the involvement of necroptosis in DMD pathogenesis. Materials/Patients and methods In vitro, muscle cells were challenged with inflammatory stimuli, with or without various protein inhibitors. Cell toxicity was monitored by the quantification of ATP content (reflecting cell survival) and protease realease (reflecting membrane permeability) In vivo, dystrophic skeletal muscles from mdx mice (a mouse model for DMD) were analyzed. Mdx mice were crossed with RIPK3 KO mice. Results In vitro, we found that TNFα can trigger necroptosis in C2C12 cell line, suggesting that muscle cells can undergo necroptosis upon inflammatory challenge. In vivo, we found evidence of necroptosis in human and mouse dystrophin-deficient muscles. By depleting RIPK3 in mdx mice, we significantly decreased myonecrosis. Conclusions Our data suggest that the necroptosis machinery is involved in the cell death affecting myofibres in DMD pathogenesis.

Highlights ► Mice lacking talin2 are viable and fertile with only a mildly dystrophic phenotype. ► Talin2 null fibroblasts show no major defects in proliferation, adhesion or migration. ► Maintaining a colony of talin2 null mice is difficult indicating an underlying defect., Mice homozygous for several Tln2 gene targeted alleles are viable and fertile. Here we show that although the expression of talin2 protein is drastically reduced in muscle from these mice, other tissues continue to express talin2 albeit at reduced levels. We therefore generated a Tln2 allele lacking the entire coding sequence (Tln2cd). Tln2cd/cd mice were viable and fertile, and the genotypes of Tln2cd/+ intercrosses were at the expected Mendelian ratio. Tln2cd/cd mice showed no major difference in body mass or the weight of the major organs compared to wild-type, although they displayed a mildly dystrophic phenotype. Moreover, Tln2cd/cd mouse embryo fibroblasts showed no obvious defects in cell adhesion, migration or proliferation. However, the number of Tln2cd/cd pups surviving to adulthood was variable suggesting that such mice have an underlying defect.

Talin 1 and 2 connect integrins to the actin cytoskeleton and regulate the affinity of integrins for ligands. In skeletal muscle, talin 1 regulates the stability of myotendinous junctions (MTJs), but the function of talin 2 in skeletal muscle is not known. Here we show that MTJ integrity is affected in talin 2-deficient mice. Concomitant ablation of talin 1 and 2 leads to defects in myoblast fusion and sarcomere assembly, resembling defects in muscle lacking β1 integrins. Talin 1/2-deficient myoblasts express functionally active β1 integrins, suggesting that defects in muscle development are not primarily caused by defects in ligand binding, but rather by disruptions of the interaction of integrins with the cytoskeleton. Consistent with this finding, assembly of integrin adhesion complexes is perturbed in the remaining muscle fibers of talin 1/2-deficient mice. We conclude that talin 1 and 2 are crucial for skeletal muscle development, where they regulate myoblast fusion,sarcomere assembly and the maintenance of MTJs.

The development and function of skeletal muscle depend on molecules that connect the muscle fiber cytoskeleton to the extracellular matrix (ECM). beta1 integrins are ECM receptors in skeletal muscle, and mutations that affect the alpha7beta1 integrin cause myopathy in humans. In mice, beta1 integrins control myoblast fusion, the assembly of the muscle fiber cytoskeleton, and the maintenance of myotendinous junctions (MTJs). The effector molecules that mediate beta1 integrin functions in muscle are not known. Previous studies have shown that talin 1 controls the force-dependent assembly of integrin adhesion complexes and regulates the affinity of integrins for ligands. Here we show that talin 1 is essential in skeletal muscle for the maintenance of integrin attachment sites at MTJs. Mice with a skeletal muscle-specific ablation of the talin 1 gene suffer from a progressive myopathy. Surprisingly, myoblast fusion and the assembly of integrin-containing adhesion complexes at costameres and MTJs advance normally in the mutants. However, with progressive ageing, the muscle fiber cytoskeleton detaches from MTJs. Mechanical measurements on isolated muscles show defects in the ability of talin 1-deficient muscle to generate force. Collectively, our findings show that talin 1 is essential for providing mechanical stability to integrin-dependent adhesion complexes at MTJs, which is crucial for optimal force generation by skeletal muscle.

We have generated mice with a floxed fak allele under the control of keratin-14-driven Cre fused to a modified estrogen receptor (CreERT2). 4-Hydroxy-tamoxifen treatment induced fak deletion in the epidermis, and suppressed chemically induced skin tumor formation. Loss of fak induced once benign tumors had formed inhibited malignant progression. Although fak deletion was associated with reduced migration of keratinocytes in vitro, we found no effect on wound re-epithelialization in vivo. However, increased keratinocyte cell death was observed after fak deletion in vitro and in vivo. Our work provides the first experimental proof implicating FAK in tumorigenesis, and this is associated with enhanced apoptosis.

Skeletal muscle is composed of many multinucleated myofibres each of which is surrounded by a connective tissue matrix that is essential for the function and the structural integrity of muscle. Apposed to each myofibre is a basement membrane, composed of a mixture of extracellular matrix (ECM) proteins, including collagen, fibronectin, glycoproteins (laminins, perlecan and nidogen) and proteoglycans. The proteins bind to multiple receptors expressed on the surface of muscle fibres: this is most notable at the level of the Z discs where an assembly of cytoskeletal proteins including dystrophin and integrins maintain continuity between the contractile apparatus, cytoskeleton and the ECM. This association of proteins is commonly referred to as the costamere, which is derived from the Latin word costa, meaning rib, because they encircle the whole muscle fibre and are arranged at regular intervals, thus conferring the appearance of a rib-like structure (Ervasti, 2003). Costameres are the means by which mechanical stress generated by contraction is diffused laterally across the myofibre. An additional structure where stress is transmitted to the ECM is the myotendinous junction (MTJ), where a connection to the tendon is made at the termini of muscle fibres (Tidball, 1991). This tight association between the muscle fibre and its surrounding matrix not only confers tensile strength to the entire muscle but also plays an important role in development, regeneration and synaptogenesis (Sanes, 2003). Indeed genetic defects in proteins that localise to the costameres and MTJs are a common cause of muscle disease, underscoring their importance in maintaining normal muscle function (Campbell and Stull, 2003).

Effective reepithelialization after injury is essential for correct wound healing. The upregulation of keratinocyte alpha3beta1 integrin during reepithelialization suggests that this adhesion molecule is involved in wound healing; however, its precise role in this process is unknown. We have shown here that retarded reepithelialization in Itga3(-/-) mouse skin wounds is due predominantly to repressed TGF-beta1-mediated responses. Specifically, expression of the inhibitor of TGF-beta1-signaling Smad7 was elevated in Itga3(-/-) keratinocytes. Indeed, in vivo blockade of Smad7 increased the rate of reepithelialization in Itga3(-/-) and WT wounds to similar levels. Our data therefore indicate that the function of alpha3beta1 integrin as a mediator of keratinocyte migration is not essential for reepithelialization but suggest instead that alpha3beta1 integrin has a major new in vivo role as an inhibitor of Smad7 during wound healing. Moreover, our study may identify a previously undocumented function for Smad7 as a regulator of reepithelialization in vivo and implicates Smad7 as a potential novel target for the treatment of cutaneous wounds.

The neuromuscular junction (NMJ) is the synapse between motoneurons and skeletal muscle, and is responsible for eliciting muscle contraction. Neurotransmission at synapses depends on the release of synaptic vesicles at sites called active zones (AZs). Various proteins of the extracellular matrix are crucial for NMJ development; however, little is known about the identity and functions of the receptors that mediate their effects. Using genetically modified mice, we find that integrin-α3 (encoded by Itga3), an adhesion receptor at the presynaptic membrane, is involved in the localisation of AZ components and efficient synaptic vesicle release. Integrin-α3 also regulates integrity of the synapse – mutant NMJs present with progressive structural changes and upregulated autophagy, features commonly observed during ageing and in models of neurodegeneration. Unexpectedly, we find instances of nerve terminal detachment from the muscle fibre; to our knowledge, this is the first report of a receptor that is required for the physical anchorage of pre- and postsynaptic elements at the NMJ. These results demonstrate multiple roles of integrin-α3 at the NMJ, and suggest that alterations in its function could underlie defects that occur in neurodegeneration or ageing.