Anatomy and Cell Biology 3309 Lecture 4: Lecture 4 - Cell Junctions and Cell Surface Modifications.docx
3 Dec 2014
School
Department
Professor
Document Summary
4 types of cell junctions on lateral domain: zonula occludens, zonula adherens, macula adherens, gap junctions. Tight (occluding) junctions: epithelial cells only, function: form barrier between cells so things can"t slip between. Adhering junctions: epithelial cells and cardiomyocytes, function: provides mechanical support, hold cells together by connecting cytoskeleton so that cells don"t rip apart (not as tight as occluding junctions) Gap junctions: most cells, function: helps cells communicate with each other, physical form. Zonula = belt, wrap all the way around the cell. Fascia = band, found in little groups/strips. Macula = spot, just one junction on its own. Tight (occluding) junctions: location: lateral domain near the apical domain so stuff from lumen doesn"t get between cells, transmembrane proteins, structure: Occludins and claudins (both have transmembrane domains that loop in and out of membrane, and have extracellular/intracellular loops. Extracellular loops of transmembrane proteins (occludin and claudin) join extracellular loops of occludin and claudin of the neighbour cell.
