Focal adhesion kinase is required for neural crest cell morphogenesis during mouse cardiovascular development
Ainara Vallejo-Illarramendi, … , Keling Zang, Louis F. Reichardt
Ainara Vallejo-Illarramendi, … , Keling Zang, Louis F. Reichardt
Published July 1, 2009
Citation Information: J Clin Invest. 2009;119(8):2218-2230. https://doi.org/10.1172/JCI38194.
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Focal adhesion kinase is required for neural crest cell morphogenesis during mouse cardiovascular development

Abstract

Neural crest cells (NCCs) participate in the remodeling of the cardiac outflow tract and pharyngeal arch arteries during cardiovascular development. Focal adhesion kinase (FAK) mediates signal transduction by integrin and growth factor receptors, each of which is important for normal cardiovascular development. To investigate the role of FAK in NCC morphogenesis, we deleted it in murine NCCs using Wnt1cre, yielding craniofacial and cardiovascular malformations resembling those observed in individuals with DiGeorge syndrome. In these mice, we observed normal cardiac NCC migration but reduced differentiation into smooth muscle within the aortic arch arteries and impaired cardiac outflow tract rotation, which resulted in a dextroposed aortic root. Moreover, within the conotruncal cushions, Fak-deficient NCCs formed a less organized mesenchyme, with reduced expression of perlecan and semaphorin 3C, and exhibited disorganized F-actin stress fibers within the aorticopulmonary septum. Additionally, absence of Fak resulted in reduced in vivo phosphorylation of Crkl and Erk1/2, components of a signaling pathway essential for NCC development. Consistent with this, both TGF-β and FGF induced FAK and Crkl phosphorylation in control but not Fak-deficient NCCs in vitro. Our results indicate that FAK plays an essential role in cardiac outflow tract development by promoting the activation of molecules such as Crkl and Erk1/2.

Authors

Ainara Vallejo-Illarramendi, Keling Zang, Louis F. Reichardt

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Figure 7

Model for FAK requirement in NCCs during cardiovascular development.

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FAK-dependent Crkl and Erk1/2 phosphorylation in NCCs. (A) Decreased Crk...
FAK signaling is required by postmigratory NCCs for appropriate cell function. In NCCs, FAK is phosphorylated by integrin activation and growth factors, such as TGF-β and FGFs. Fak-deficient NCCs are unable to propagate or integrate certain integrin and growth factor signals. Specifically, during outflow tract septation, Crkl and Erk1/2 phosphorylation is impaired in Fak-deficient NCCs, leading to cardiac developmental defects that recapitulate DiGeorge syndrome. Deficient Crkl phosphorylation potentially affects Crkl binding ability, through its SH2 domain, to other proteins, such as paxillin and p130CAS, and translocation of Crkl to focal adhesions. Therefore, activation of Rac1 and Cdc42 is potentially affected in Fak-deficient NCCs, which results in reduced cortactin localization to the cell periphery, abnormal cell morphology, and cytoskeletal reorganization.