GRE Subject Test: Biochemistry, Cell, and Molecular Biology › Help with Junction Proteins
Which of the following proteins forms channels that permit electrical communication between cells across gap junctions?
Connexin
Cadherin
Ephrin
Tubulin
Catenin
Most of the other proteins listed are structural, but do not form any kind of pore or channel through which an electrical message can cross. Connexins are required for this function of gap junctions.
What are the two major proteins that comprise tight junctions**,** cellular junctions that prevent fluids from traveling between cells and generally contribute to morphology by holding cells together?
Claudins and occludins
Claudins and adherins
Occludins and connexins
Connexins and integrins
Claudins and protocadherins
While each of the proteins listed contribute to cell structure and function, the tight junction requires claudins and occludins to anchor the cytoskeleton of two adjacent cells to one another. These are the primary structural components of tight junctions.