Question

125.

An epithelial in the respiratory tract disengages from fibronectin and other proteins in the extracellular matrix (ECM). The cell responds by initiating apoptosis, a cellular suicide pathway. The transmembrane protein that is no longer binding to fibronectin, and therefore, is no longer transmitting signals from the ECM to the cell is: A. Integrin B. alpha-keratin C. Cadherin D. beta-keratin

Answer 1

Q:An epithelial cell in the respiratory tract disengages from fibronectin and other proteins in the extracellular matrix (ECM). The cell responds by initiating apoptosis, a cellular suicide pathway. The transmembrane protein that is no longer binding to fibronectin, and therefore, is no longer transmitting signals from the ECM to the cell is

Ans: Integrin

Integrins are the principal receptors used by animal cells to bind to the extracellular matrix. They are heterodimers and function as transmembrane linkers between the extracellular matrix and the actin cytoskeleton. Collagen connects to integrin proteins in the plasma membrane through fibronectin. Integrins anchor the cell to the extracellular matrix.

Cadherins

Cadherins are a type of cell adhesion molecule that is important in the formation of adherens junctions to bind cells with each other. Integrins mediate adhesion between the cell and its extracellular matrix (ECM), and cadherins mediate homotypic adhesion between cells.

Alpha keratin and Beta keratin

Keratin is an important protein in the epidermis. Keratin has two main functions: to adhere cells to each other and to form a protective layer on the outside of the skin. In epithelial cells, keratin proteins inside the cell attach to proteins called desmosomes on the surface. Alpha keratin occurs in mammals whereas the beta keratin occurs in the epidermis of reptiles.