Background: Nemaline myopathy is a neuromuscular disorder characterized by the presence of nemaline bodies in patient muscles. 20% of the cases are associated with alpha-skeletal muscle actin mutations. We previously showed that actin mutations can cause four different biochemical phenotypes and that expression of NM associated actin mutants in fibroblasts, myoblasts and myotubes induces a range of cellular defects.
Findings: We conducted the same biochemical experiments for twelve new actin mutants associated with nemaline myopathy. We observed folding and polymerization defects. Immunostainings of these and eight other mutants in transfected cells revealed typical cellular defects such as nemaline rods or aggregates, decreased incorporation in F-actin structures, membrane blebbing, the formation of thickened actin fibres and cell membrane blebbing in myotubes.
Conclusion: Our results confirm that NM associated alpha-actin mutations induce a range of defects at the biochemical level as well as in cultured fibroblasts and muscle cells.
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http://dx.doi.org/10.1186/1756-0500-2-40 | DOI Listing |
Tropomyosin is an actin-binding protein that plays roles ranging from regulating muscle contraction to controlling cytokinesis and cell migration. The simple nematode provides a useful model for studying the core functions of tropomyosin in an animal, having a relatively simple anatomy, and a single tropomyosin gene, , that produces seven isoforms. Three higher molecular weight isoforms (LEV-11A, D, O) regulate contraction of body wall and other muscles, but comparatively less is known of the functions of four lower molecular weight isoforms (LEV-11C, E, T, U).
View Article and Find Full Text PDFNeurons use cell-adhesion molecules (CAMs) to interact with other neurons and the extracellular environment: the combination of CAMs specifies migration patterns, neuronal morphologies, and synaptic connections across diverse neuron types. Yet little is known regarding the intracellular signaling cascade mediating the CAM recognitions at the cell surface across different neuron types. In this study, we investigated the neural developmental role of Afadin , a cytosolic adapter protein that connects multiple CAM families to intracellular F-actin.
View Article and Find Full Text PDFOne of the long-standing questions in cell signaling field to identify and characterize key signaling nodes out of a complex network. Phospholipase Cγ1 ( ) was identified as the most frequently mutated gene in adult T-cell leukemia/lymphoma, suggesting a critical function of PLCG1 in driving T cell activation. However, it remains unclear how these mutations regulate T cell physiology and pathology.
View Article and Find Full Text PDFCalcif Tissue Int
January 2025
Jerry L. Pettis Memorial VA Medical Center, VA Loma Linda Healthcare System, Loma Linda, CA, USA.
This study assessed the feasibility of miR17 ~ 92-based antiresorptive strategy by determining the effects of conditional transgenic (cTG) overexpression of miR17 ~ 92 in myeloid cells on bone and osteoclasts. Osteoclasts of male and female cTG mutant mice each showed 3- to fivefold overexpression of miR17 ~ 92 cluster genes compared to those of age- and sex-matched wildtype (WT) littermates. Male but not female cTG mutant mice had more trabecular and cortical bones as well as lower bone resorption reflected by reduction in osteoclast number and resorbing surface.
View Article and Find Full Text PDFCommun Biol
December 2024
Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA.
Integrin_K Channel_Complexes (IKCs), are implicated in neurodevelopment and cause developmental and epileptic encephalopathy (DEE) through mechanisms that were poorly understood. Here, we investigate the function of neocortical IKCs formed by voltage-gated potassium (Kv) channels Kcnb1 and α5β5 integrin dimers in wild-type (WT) and homozygous knock-in (KI) Kcnb1 mouse model of DEE. Kcnb1 mice suffer from severe cognitive deficit and compulsive behavior.
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