@article {967, title = {Biallelic mutations in LAMA5 disrupts a skeletal noncanonical focal adhesion pathway and produces a distinct bent bone dysplasia.}, journal = {EBioMedicine}, volume = {62}, year = {2020}, month = {2020 Dec}, pages = {103075}, abstract = {

BACKGROUND: Beyond its structural role in the skeleton, the extracellular matrix (ECM), particularly basement membrane proteins, facilitates communication with intracellular signaling pathways and cell to cell interactions to control differentiation, proliferation, migration and survival. Alterations in extracellular proteins cause a number of skeletal disorders, yet the consequences of an abnormal ECM on cellular communication remains less well understood METHODS: Clinical and radiographic examinations defined the phenotype in this unappreciated bent bone skeletal disorder. Exome analysis identified the genetic alteration, confirmed by Sanger sequencing. Quantitative PCR, western blot analyses, immunohistochemistry, luciferase assay for WNT signaling were employed to determine RNA, proteins levels and localization, and dissect out the underlying cell signaling abnormalities.~ Migration and wound healing assays examined cell migration properties.

FINDINGS: This bent bone dysplasia resulted from biallelic mutations in LAMA5, the gene encoding the alpha-5 laminin basement membrane protein. This finding uncovered a mechanism of disease driven by ECM-cell interactions between alpha-5-containing laminins, and integrin-mediated focal adhesion signaling, particularly in cartilage. Loss of LAMA5 altered β1 integrin signaling through the non-canonical kinase PYK2 and the skeletal enriched SRC kinase, FYN. Loss of LAMA5 negatively impacted the actin cytoskeleton, vinculin localization, and WNT signaling.

INTERPRETATION: This newly described mechanism revealed a LAMA5-β1 Integrin-PYK2-FYN focal adhesion complex that regulates skeletogenesis, impacted WNT signaling and, when dysregulated, produced a distinct skeletal disorder.

FUNDING: Supported by NIH awards R01 AR066124, R01 DE019567, R01 HD070394, and U54HG006493, and Czech Republic grants INTER-ACTION LTAUSA19030, V18-08-00567 and GA19-20123S.

}, issn = {2352-3964}, doi = {10.1016/j.ebiom.2020.103075}, author = {Barad, Maya and Csukasi, Fabiana and Bosakova, Michaela and Martin, Jorge H and Zhang, Wenjuan and Paige Taylor, S and Lachman, Ralph S and Zieba, Jennifer and Bamshad, Michael and Nickerson, Deborah and Chong, Jessica X and Cohn, Daniel H and Krejci, Pavel and Krakow, Deborah and Duran, Ivan} } @article {349, title = {A postnatal role for embryonic myosin revealed by MYH3 mutations that alter TGFβ signaling and cause autosomal dominant spondylocarpotarsal synostosis.}, journal = {Sci Rep}, volume = {7}, year = {2017}, month = {2017 02 16}, pages = {41803}, abstract = {

Spondylocarpotarsal synostosis (SCT) is a skeletal disorder characterized by progressive vertebral, carpal and tarsal fusions, and mild short stature. The majority of affected individuals have an autosomal recessive form of SCT and are homozygous or compound heterozygous for nonsense mutations in the gene that encodes the cytoskeletal protein filamin B (FLNB), but a subset do not have FLNB mutations. Exome sequence analysis of three SCT patients negative for FLNB mutations identified an autosomal dominant form of the disease due to heterozygosity for missense or nonsense mutations in MYH3, which encodes embryonic myosin. Cells transfected with the MYH3 missense mutations had reduced TGFβ signaling, revealing a regulatory role for embryonic myosin in the TGFβ signaling pathway. In wild-type mice, there was persistent postnatal expression of embryonic myosin in the small muscles joining the neural arches of the spine suggesting that loss of myosin function in these muscles contribute to the disease. Our findings demonstrate that dominant mutations in MYH3 underlie autosomal dominant SCT, identify a postnatal role for embryonic myosin and suggest that altered regulation of signal transduction in the muscles within the spine may lead to the development of vertebral fusions.

}, keywords = {Abnormalities, Multiple, Alleles, Bone Morphogenetic Proteins, Cytoskeletal Proteins, Female, Genes, Dominant, Genotype, Humans, Lumbar Vertebrae, Male, Musculoskeletal Diseases, Mutation, Myosins, Phenotype, Radiography, Scoliosis, Signal Transduction, Synostosis, Thoracic Vertebrae, Transforming Growth Factor beta, Whole Exome Sequencing}, issn = {2045-2322}, doi = {10.1038/srep41803}, author = {Zieba, Jennifer and Zhang, Wenjuan and Chong, Jessica X and Forlenza, Kimberly N and Martin, Jorge H and Heard, Kelly and Grange, Dorothy K and Butler, Merlin G and Kleefstra, Tjitske and Lachman, Ralph S and Nickerson, Deborah and Regnier, Michael and Cohn, Daniel H and Bamshad, Michael and Krakow, Deborah} }