CFTR and cystic fibrosis: Although enhanced sphingolipid synthesis in CF was shown to induce ceramide and sphingomyelin mass increase, the CFTR silenced human airway epithelial cell line exhibited ~60% lower GM1 ganglioside than control cells and was unable to migrate, showing impaired activation of β1-integrin, phosphorylation of focal adhesion kinase, and Crk-associated substrate.