Epithelial Cells

Epithelial cells form sheets that line the cavities and surfaces of various organs, most notably in the digestive, integumentary, reproductive, urinary, and respiratory systems. Epithelial cells exhibit a diversity of functions, including secretion, absorption, barrier formation, and sensation. To perform these functions, epithelial cells establish a polarized geometry with unique apical and basolateral domains and stereotypic cell shapes. A cortical actin filament network associated with the spectrin-based membrane skeleton is essential for establishing the geometry of polarized epithelial cells. Cortical actin in epithelial cells is associated with tropomodulin (Tmod), which caps the pointed ends of actin filaments, and tropomyosin (TM), which decorates and stabilizes actin filaments along their length. Our research in this area has investigated the hypothesis that Tmod and TM play structural roles in the cortical actin network and membrane skeleton of epithelial cells via their regulation of actin filament dynamics and stability.

 

Key questions are:

 

•  How do perturbations in the expression of Tmod or TM affect actin filament assembly, architecture, or stability in polarized epithelial sheets?

 

•  What are the roles of actin, Tmod, and TM in the organization of the cortical actin network and membrane skeleton of epithelial cells?

 

•  How do actin filaments, Tmod, and TM facilitate the establishment of polarized epithelial cells along with their stereotypical shapes and packing geometries in cell sheets?

 

•  How do the protein components of the cortical actin cytoskeleton of epithelial cells facilitate the separation of lateral, basal, and apical membranes into functionally distinct compartments?