Regulation of Myoblast Proliferation and Differentiation by Anoctamin 5 and 6

Abstract

Anoctamin 5 (ANO5) and 6 (ANO6) belong to a conserved gene family (anoctamins, also known as TMEM16 ), which encode for proteins predicted to have eight transmembrane domains and putative Ca2+-activated chloride channel (CaCC) activity. Genetic defects in this gene family result in a number of human diseases. In particular, mutations in ANO5 have been linked to gnathodiaphyseal dysplasia 1 (GDD1), limb-girdle muscular dystrophy (LGMD2L), and Miyoshi myopathy (MMD3), while mutations in ANO6 cause a bleeding syndrome. However, the biological functions of these anoctamins in skeletal muscle are largely unknown. In this study we examined the roles of Ano5 and Ano6 in C2C12 proliferation and differentiation. Our data showed that Ano6 but not Ano5 plays an essential role in C2C12 myoblast proliferation, likely via regulating the ERK/AKT signaling pathway. In addition, Ano5 or Ano6deficiency alone does not affect the myogenic differentiation program of C2C12 cells, however knocking down both Ano5and Ano6 remarkably promotes C2C12 myoblast differentiation. Our data demonstrate that Ano5 and Ano6 together may play an important role in regulating the switch from proliferation to differentiation during myogenesis. Further investigation will focus on the mechanisms of Ano5 and Ano6 in this regulatory process.