MIT20_441JF09_lec05a_iy

MIT20_441JF09_lec05a - 1 2.79J/3.96J/20.441J/HST522J Biomaterials-Tissue Interactions Structure and function of naturally occurring extracellular

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Unformatted text preview: 1 2.79J/3.96J/20.441J/HST522J Biomaterials-Tissue Interactions Structure and function of naturally occurring extracellular matrices (ECMs). 2 The insoluble regulator in a unit cell process is part of an ECM macromolecule Cell + Insoluble Regulator Product Soluble Regulator A Soluble Regulator B Control volume dV Unit cell process confined conceptually in a control volume dV 3 100 μ m 100 μ m A biologically active model of ECM acts as an insoluble regulator of cell function 4 Integrin adhesion to collagen at the FOGER ligand Emsley et al., 2000 Knight et al., 2000 Phenotype change: fibroblast α 2 β 1 integrin binds to collagen ligand GFOGER (hexapeptide) Courtesy of Elsevier, Inc., http://www.sciencedirect.com . Used with permission. 5 The Extracellular Matrices (ECMs) (summary of structure and function) ¡ Insoluble macromolecular networks. ¡ Structure varies with organ; but different ECMs comprise few types of macromolecules (mostly collagen, elastin, proteoglycans) plus water (65%). ¡ ECM does not migrate, proliferate, synthesize proteins or contain DNA! ¡ Give and take of signals with cells. Ligands on ECM surface interact specifically with cell receptors (integrins). ¡ Partly determine the state of differentiation of cells. 6 The Extracellular Matrices… (summary of structure and function) ¡ Possibly play role of memory storage device which is used to record events (e.g., a recent cell migration), thereby informing cells of what has already been done and acting as “arrow” in a kinetic process. ¡ Often bind cytokines and growth factors and act as reservoirs of such molecules. ¡ Loss of cell-matrix contact characterizes tumor cells just prior to spreading of cancer from one organ to another (metastasis). ¡ Determines the shape of animals and maintains positional homeostasis of organs. ¡ Recently, certain synthetic ECM models have induced organ regeneration in adults . 7 The major ECM molecules in tissues 1. Collagens. 2. Elastin. 3. Proteoglycans and glycosaminoglycans (GAGs). 4. Cell-adhesion molecules (fibronectin, laminin, others). [Water (about 65% of tissue weight).] 8 Schematic view of ECM Figure by MIT OpenCourseWare. After Ricci. 9 The Extracellular Matrices. Part I. Collagens 10 Hierarchy of structural order in proteins Primary structure : the complete sequence of amino acids (AA) in the polypeptide chain. Scale: 1 nm....
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This note was uploaded on 11/11/2011 for the course BIO 2.797j taught by Professor Matthewlang during the Fall '06 term at MIT.

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MIT20_441JF09_lec05a - 1 2.79J/3.96J/20.441J/HST522J Biomaterials-Tissue Interactions Structure and function of naturally occurring extracellular

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