Nesprin-2 interacts with meckelin and mediates ciliogenesis via remodelling of the actin cytoskeleton.
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.
Dawe
Helen R
HR
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
Adams
Matthew
M
Wheway
Gabrielle
G
Szymanska
Katarzyna
K
Logan
Clare V
CV
Noegel
Angelika A
AA
Gull
Keith
K
Johnson
Colin A
CA
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
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