Altered Twist1 and Hand2 dimerization is associated with Saethre-Chotzen syndrome and limb abnormalities.
Autosomal dominant mutations in the gene encoding the basic helix-loop-helix transcription factor Twist1 are associated with limb and craniofacial defects in humans with Saethre-Chotzen syndrome. The molecular mechanism underlying these phenotypes is poorly understood. We show that ectopic expression of the related basic helix-loop-helix factor Hand2 phenocopies Twist1 loss of function in the limb and that the two factors have a gene dosage-dependent antagonistic interaction. Dimerization partner choice by Twist1 and Hand2 can be modulated by protein kinase A- and protein phosphatase 2A-regulated phosphorylation of conserved helix I residues. Notably, multiple Twist1 mutations associated with Saethre-Chotzen syndrome alter protein kinase A-mediated phosphorylation of Twist1, suggesting that misregulation of Twist1 dimerization through either stoichiometric or post-translational mechanisms underlies phenotypes of individuals with Saethre-Chotzen syndrome.
Firulli, BA; Krawchuk, D; Centonze, VE; Vargesson, N; Virshup, DM; Conway, SJ; Cserjesi, P; Laufer, E; Firulli, AB
Volume / Issue
Start / End Page
Pubmed Central ID
International Standard Serial Number (ISSN)
Digital Object Identifier (DOI)