CSB331H1 Lecture 2: Lecture 2.pdf
24 Feb 2015
School
Department
Course
Professor
Document Summary
Epithelial tissue manages mechanical stress, provides tissue with stability. Epithelial cells are polarized: apical-lateral-basal polarity, as well as planar polarity (position/direction in a plane) Tight junctions (zona occludens) near apical end. Adherens junctions (zona adherens) junctions not directly attached to cytoskeleton, adaptors required. Migrating cells also have a front-rear polarity. Mechanotransduction converts mechanical stimuli (rigidity, stretching) into chemical signals to regulate behavior and function. Non-muscle cells also have actin-myosin mediated contractions. Focal adhesion between the cell and the surface integrins required for focal adhesion shuttled around to maintain proper movement. Junctions too small to be resolved by light microscope. Extracellular cadherins, intracellular catenins connecting to actin. N-cadherin in neurons and other contractile tissue. Loss of e-cadherin leads to emt, gain of e-cadherin leads to met. Cadherins generally homophilic (e-cadherins to other e-cadherins, maintain homogeneous cell type/tissue layers) Ca binding between domains (2-3 ions per ridge) Small changes in loop sequences alters the affinity for binding partners, specificity.
