Regulation of the Notch signaling pathway in skeletal muscle and in muscle disease



Poster Number: 102


Mekala Gunasekaran, PhD, University of Minnesota, Natalya Wells, University of Minnesota, Audrey Daugherty, University of Minnesota, Atsushi Asakura, PhD, University of Minnesota, Isabelle Draper, PhD, Tufts University, Peter Kang, MD, University of Minnesota

The evolutionarily conserved Notch signaling pathway is vital for the development and maintenance of multiple tissues. In skeletal muscle, the Notch pathway is involved in myogenesis and muscle stem cell self-renewal. The gene MEGF10 is associated with an extremely rare inherited muscle disease, MEGF10 myopathy. The protein product, also named MEGF10, is an orphan receptor that interacts with Notch1 at their intracellular domains and is regulated in part by tyrosine phosphorylation. Since the discovery of MEGF10 as a muscle disease gene, two other genes whose protein products interact with the Notch pathway have been linked to muscle disease: POGLUT1 and JAG2. The splice regulator hnRNP L is predicted to target several muscle genes. Our studies in Drosophila have shown altered splicing levels of Dys (dystrophin) and Tm2 (tropomyosin2) in the setting of downregulation of Sm (smooth); these are the fly orthologs of DMD, several TPM (Tropomyosin) genes, and hnRNP L, respectively. We have also observed altered expression of Notch pathway components in vitro when hnRNP L is downregulated, and in mouse skeletal muscles deficient in Megf10. Ongoing studies are examining the question of whether hnRNP L and its orthologs are master splice regulators of the Notch signaling pathway during key steps in skeletal muscle development, repair and pathogenesis in muscle diseases.