麻省理工大学：《生物工程》教学讲义（英文版）lec 25 slides

Cell Adhesion · Structural Integrity External Sensing Migration Requlation of transport Communication adish Chapter 22 Kamm Chapter 2

Cell Adhesion • Structural Integrity • External Sensing • Migration • Regulation of Transport • Communication Lodish Chapter 22 Kamm Chapter 2

Overview of the types of molecules that bind cells to each other and to the extracellular matrix Cell-cell adhesions Cell-adhesion molecules Actin or intermediate filaments Transmembrane proteogly P membrane Cell matrix adhesions Collagen Glycosaminoglycans Matrix Fibronectin proteoglycan or laminin core protein

Overview of the types of molecules that bind cells to each other and to the extracellular matrix

Cell adhesion molecules and their characteristics Family Location and/or Comments function recognized Integrins focal adhesions (E)fibronectin, relatively low hemi-desmosomes, collagen, laminin, affinities leukocyte immunoglobulins, (KD- 10-10 ("spreading") O actin filaments mol/liter) cell-matrix adhesion but also in some circulating cells and carbohydrates require Ca endothelial cells rolling " adhesion Ig superfamily mportant in Integrins, (immunoglobulin) homophilic desmosomes (actin flame RD Kamm 2003

Cell adhesion molecules and their characteristics Family Location and/or Ligands Comments function recognized integrins focal adhesions, (E) fibronectin, relatively low hemi-desmosomes, leukocy te collagen, laminin, immunoglobulins, affinities (KD~ 10-6-10-8 ("spreading") (I) actin filaments mol/liter) adhesion, primarily cell-matrix adhesion but also in some cell-cell adhesions selectins circulating cells and carbohydrates require Ca 2+ endothelial cells, "rolling" adhesion Ig superfamily important in integrins, (immunoglobulin) cadherens immune response adherens junctions, homophillic (E) homophillic, require Ca 2+ desmosomes (I) actin filaments, intermediate filaments RD Kamm 2003

Adhesion complexes Junction tvpe Function Extracellular or ntracellular adjacent cell attachment attachment Adherens structural, cell-cell or cell- ECM proteins or actin filaments matrix djacent cell structural. cell-cell cadherin intermediate filaments Hemidesmosome structural cell-matrix basal lamina via intermediate ntegrins filaments Focal adhesions structural cell-matrix ECM proteins actin filaments Tight j ulate transport between cells and along cell Gap junctions cell-cell communication channels formed by connexin via ion and small molecule subun its Table 2. Adhe sion complexes

Adhesion complexes Junction type Function Extracellular or adjacent cell attachment Intracellular attachment Adherens structural, cell-cell or cell￾matrix ECM proteins or cadherins in actin filaments Desmosome structural, cell-cell adjacent cell cadherin intermediate filaments Hemidesmosome structural, cell-matrix basal lamina via intermediate Focal adhesions Tight junction structural, cell-matrix regulate transport between cells and along cell membrane integrins ECM proteins via integrins filaments actin filaments Gap junctions cell-cell communication via ion and small molecule chann els formed by connex in subun its exchange Table 2. Adhe sion co mplexes

Gap junctions allow small molecules to pass between adjacent cells Gap-junction channel c Connexin Intra-cellula Connexin cOo" subunit Cell membrane

Gap junctions allow small molecules to pass between adjacent cells

Adherens junctions in epithelial cel Cytosol Apical surface Exterior -Cadherin Microvillus一 Cytosol Homophilic proteins Cadherin family Tight junctions Structural weld Adherens junction Adherens junction Lateral surface Spot Intermediate Basal surace Basal lamina Hemidesmosome Desmosome Desmosomes: " spot welds

Image removed due to copyright considerations See Orsello, C E, D A Lauffenburger and D. A. Hammer. "Molecular properties in cell adhesion: a physical and engineering perspective. " TRENDS in Biotechnology, Vol 19 No. 8(August 2001)

Image removed due to copyright considerations. See Orsello, C.E., D. A. Lauffenburger and D. A. Hammer. “Molecular properties in cell adhesion: a physical and engineering perspective.” TRENDS in Biotechnology, Vol. 19 No. 8 (August 2001)

Selectins and other caMs participate in leukocyte extravasation 1. Free leukocyte Selectin ligand 2. Transient rolling (specific leukocyte carbohydrate) .B2 integrin 3. Leukocyte activation PAF receptor rolling and firm adhesion ICAM-1 Endothelial (PAF activates integrin) activation Endothelial cell 1, P-selectin PAF synthesis Leukocyte adhesion (integrin bonds to 4. Extravasation ICAM-1)

Selectins and other CAMs participate in leukocyte extravasation

Integrins mediate weak cell-matrix and cell-cell interactions Cell-matrix adhesion is modulated by changes in the activity and number of Image removed due to copyright considerations integrins See [Lodish] Table 22-2 PubmedUrl:http:/www.ncbi.nlmnih.gov/books/bv.fcgi?rid-mcb.table6528 De-adhesion factors promote cell migration and can remodel the cell surface

Integrins mediate weak cell-matrix and cell-cell interactions Cell-matrix adhesion is modulated by changes in the activity and number of integrins Image removed due to copyright considerations. See [Lodish] Table 22-2. PubMed URL: http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.table.6528 De-adhesion factors promote cell migration and can remodel the cell surface

Integrin-containing junctions connect cells to the substratum Image removed due to copyright considerations See [Lodish] Figure 22-9 PubmedUrl:http://www.ncbi.nlm.nihgov/books/bv.fcgi?rd-mcb.figgrp.6533

Integrin-containing junctions connect cells to the substratum Image removed due to copyright considerations. See [Lodish] Figure 22-9. PubMed URL: http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.figgrp.6533