Insights into the molecular pathogenesis of cardiospondylocarpofacial syndrome: MAP3K7 c.737-7A > G variant alters the TGFβ-mediated α-SMA cytoskeleton assembly and autophagy

Biochim Biophys Acta Mol Basis Dis. 2020 Jun 1;1866(6):165742. doi: 10.1016/j.bbadis.2020.165742. Epub 2020 Feb 24.


Transforming growth factor beta-activated kinase 1 (TAK1) is a highly conserved kinase protein encoded by MAP3K7, and activated by multiple extracellular stimuli, growth factors and cytokines. Heterozygous variants in MAP3K7 cause the cardiospondylocarpofacial syndrome (CSCFS) which is characterized by short stature, dysmorphic facial features, cardiac septal defects with valve dysplasia, and skeletal anomalies. CSCFS has been described in seven patients to date and its molecular pathogenesis is only partially understood. Here, the functional effects of the MAP3K7 c.737-7A > G variant, previously identified in a girl with CSCFS and additional soft connective tissue features, were explored. This splice variant generates an in-frame insertion of 2 amino acid residues in the kinase domain of TAK1. Computational analysis revealed that this in-frame insertion alters protein dynamics in the kinase activation loop responsible for TAK1 autophosphorylation after binding with its interactor TAB1. Co-immunoprecipitation studies demonstrate that the ectopic expression of TAK1-mutated protein impairs its ability to physically bind TAB1. In patient's fibroblasts, MAP3K7 c.737-7A > G variant results in reduced TAK1 autophosphorylation and dysregulation of the downstream TAK1-dependent signaling pathway. TAK1 loss-of-function is associated with an impaired TGFβ-mediated α-SMA cytoskeleton assembly and cell migration, and defective autophagy process. These findings contribute to our understanding of the molecular pathogenesis of CSCFS and might offer the rationale for the design of novel therapeutic targets.

Keywords: Cardiospondylocarpofacial syndrome; Connective tissue; TAB1; TAK1; TGFβ; α-SMA cytoskeleton.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Abnormalities, Multiple / physiopathology
  • Actins / genetics*
  • Adaptor Proteins, Signal Transducing / genetics
  • Autophagy / genetics*
  • Child
  • Cytoskeleton / genetics
  • Female
  • Fibroblasts / metabolism
  • Hearing Loss, Bilateral / genetics*
  • Hearing Loss, Bilateral / physiopathology
  • Humans
  • Loss of Function Mutation / genetics
  • MAP Kinase Kinase Kinases / genetics*
  • Mitral Valve Insufficiency / genetics*
  • Mitral Valve Insufficiency / physiopathology
  • Mutation / genetics
  • Osteosclerosis / genetics*
  • Osteosclerosis / physiopathology
  • Phosphorylation / genetics
  • Polymorphism, Single Nucleotide / genetics
  • Protein Binding / genetics
  • Signal Transduction / genetics
  • Transforming Growth Factor beta / genetics


  • ACTA2 protein, human
  • Actins
  • Adaptor Proteins, Signal Transducing
  • TAB1 protein, human
  • Transforming Growth Factor beta
  • MAP Kinase Kinase Kinases
  • MAP kinase kinase kinase 7

Supplementary concepts

  • Forney Robinson Pascoe syndrome