@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 {695, title = {Dominant-negative SOX9 mutations in campomelic dysplasia.}, journal = {Hum Mutat}, volume = {40}, year = {2019}, month = {2019 12}, pages = {2344-2352}, abstract = {

Campomelic dysplasia (CD) is an autosomal dominant, perinatal lethal skeletal dysplasia characterized by a small chest and short long bones with bowing of the lower extremities. CD is the result of heterozygosity for mutations in the gene encoding the chondrogenesis master regulator, SOX9. Loss-of-function mutations have been identified in most CD cases so it has been assumed that the disease results from haploinsufficiency for SOX9. Here, we identified distal truncating SOX9 mutations in four unrelated CD cases. The mutations all leave the dimerization and DNA-binding domains intact and cultured chondrocytes from three of the four cases synthesized truncated SOX9. Relative to CD resulting from haploinsufficiency, there was decreased transactivation activity toward a major transcriptional target, COL2A1, consistent with the mutations exerting a dominant-negative effect. For one of the cases, the phenotypic consequence was a very severe form of CD, with a pronounced effect on vertebral and limb development. The data identify a novel molecular mechanism of disease in CD in which the truncated protein leads to a distinct and more significant effect on SOX9 function.

}, issn = {1098-1004}, doi = {10.1002/humu.23888}, author = {Csukasi, Fabiana and Duran, Ivan and Zhang, Wenjuan and Martin, Jorge H and Barad, Maya and Bamshad, Michael and Weis, Mary Ann and Eyre, David and Krakow, Deborah and Cohn, Daniel H} } @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} } @article {343, title = {An inactivating mutation in intestinal cell kinase, ICK, impairs hedgehog signalling and causes short rib-polydactyly syndrome.}, journal = {Hum Mol Genet}, volume = {25}, year = {2016}, month = {2016 09 15}, pages = {3998-4011}, abstract = {

The short rib polydactyly syndromes (SRPS) are a group of recessively inherited, perinatal-lethal skeletal disorders primarily characterized by short ribs, shortened long bones, varying types of polydactyly and concomitant visceral abnormalities. Mutations in several genes affecting cilia function cause SRPS, revealing a role for cilia function in skeletal development. To identify additional SRPS genes and discover novel ciliary molecules required for normal skeletogenesis, we performed exome sequencing in a cohort of patients and identified homozygosity for a missense mutation, p.E80K, in Intestinal Cell Kinase, ICK, in one SRPS family. The p.E80K mutation abolished serine/threonine kinase activity, resulting in altered ICK subcellular and ciliary localization, increased cilia length, aberrant cartilage growth plate structure, defective Hedgehog and altered ERK signalling. These data identify ICK as an SRPS-associated gene and reveal that abnormalities in signalling pathways contribute to defective skeletogenesis.

}, keywords = {Abnormalities, Multiple, Cilia, Exome, Female, Hedgehog Proteins, Humans, Infant, MAP Kinase Signaling System, Pedigree, Pregnancy, Protein-Serine-Threonine Kinases, Sequence Analysis, DNA, Short Rib-Polydactyly Syndrome, Signal Transduction, Skeleton}, issn = {1460-2083}, doi = {10.1093/hmg/ddw240}, author = {Paige Taylor, S and Kunova Bosakova, Michaela and Varecha, Miroslav and Balek, Lukas and Barta, Tomas and Trantirek, Lukas and Jelinkova, Iva and Duran, Ivan and Vesela, Iva and Forlenza, Kimberly N and Martin, Jorge H and Hampl, Ales and Bamshad, Michael and Nickerson, Deborah and Jaworski, Margie L and Song, Jieun and Ko, Hyuk Wan and Cohn, Daniel H and Krakow, Deborah and Krejci, Pavel} }