title: Nesprin-2 interacts with meckelin and mediates ciliogenesis via remodelling of the actin cytoskeleton.
abstract: Meckel-Gruber syndrome (MKS) is a severe autosomal recessively inherited disorder caused by mutations in genes that encode components of the primary cilium and basal body. Here we show that two MKS proteins, MKS1 and meckelin, that are required for centrosome migration and ciliogenesis interact with actin-binding isoforms of nesprin-2 (nuclear envelope spectrin repeat protein 2, also known as Syne-2 and NUANCE). Nesprins are important scaffold proteins for maintenance of the actin cytoskeleton, nuclear positioning and nuclear-envelope architecture. However, in ciliated-cell models, meckelin and nesprin-2 isoforms colocalized at filopodia prior to the establishment of cell polarity and ciliogenesis. Loss of nesprin-2 and nesprin-1 shows that both mediate centrosome migration and are then essential for ciliogenesis, but do not otherwise affect apical-basal polarity. Loss of meckelin (by siRNA and in a patient cell-line) caused a dramatic remodelling of the actin cytoskeleton, aberrant localization of nesprin-2 isoforms to actin stress-fibres and activation of RhoA signalling. These findings further highlight the important roles of the nesprins during cellular and developmental processes, particularly in general organelle positioning, and suggest that a mechanistic link between centrosome positioning, cell polarity and the actin cytoskeleton is required for centrosomal migration and is essential for early ciliogenesis.
authors: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
authors: Helen R
authors: HR
authors: Dawe
authors: Matthew
authors: M
authors: Adams
authors: Gabrielle
authors: G
authors: Wheway
authors: Katarzyna
authors: K
authors: Szymanska
authors: Clare V
authors: CV
authors: Logan
authors: Angelika A
authors: AA
authors: Noegel
authors: Keith
authors: K
authors: Gull
authors: Colin A
authors: CA
authors: Johnson
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002478:Cells, Cultured; D002923:Cilia / Q000378:metabolism*; D003599:Cytoskeleton; D005347:Fibroblasts / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D047468:Immunoprecipitation; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D020798:Two-Hybrid System Techniques
chemical_list: D000199:Actins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; C485904:SYNE2 protein, human; C468846:TMEM67 protein, human