Transcript for:
L5_Cell adhesion and junctional complexes

Title: Cell types and subcellular structures URL Source: blob://pdf/49e82180-de13-43ab-b93d-3679829cd37f Markdown Content: Cell adhesion and junctional complexes Lecture 5 4BBY1030 Cell Biology & Neuroscience Institute of Psychology, Psychiatry and Neuroscience Neuroscience Education Dr Clemens Kiecker Dr Clemens Kiecker Topic title: Cell types and subcellular structures Learning outcomes By the end of this lecture you should be able to explain: a) explain how cells adhere to each other (cell-cell adhesion b) explain how cells adhere to extracellular matrix (cell-matrix adhesion) c) describe the composition of the extracellular matrix Dr Clemens Kiecker Topic title: Cell types and subcellular structures Chapter 1 # Extracellular matrix (ECM) 3Dr Clemens Kiecker Topic title: Cell types and subcellular structures Two types of extracellular matrix 4 Epithelium (Cells are tightly packed, binding to each other) Mesenchyme (Cells are sparse) Section of mouse embryo, Nagai et al. J Cell Biol 2000;150:1499- 1506 > 10 m Basement membrane/basal lamina 2D sheet on which epithelial cells reside Essential Cell Biology Fibrillar matrix 3D matrix composed of various fibres, in which cells such as fibroblasts are buried Mori et al. 2008, J Exp Med. 205: 43-51 > Cell > `Dr Clemens Kiecker Topic title: Cell types and subcellular structures Basement membrane/basal lamina > 5 Underlies epithelia and surrounds some non- epithelial cells Main components: Collagen IV Laminin Nidogen Perlecan Dr Clemens Kiecker Topic title: Cell types and subcellular structures Fibrillar matrix > 6 Deposited and constantly re-modelled by embedded cells Main components: Collagen I Fibronectin Elastin Proteoglycans Dr Clemens Kiecker Topic title: Cell types and subcellular structures Chapter 2 # Cell adhesion and junctions 7Dr Clemens Kiecker Topic title: Cell types and subcellular structures Types of junctional complexes 8 ` A. Tight junction B. Adherens junction C. Desmosome D. Gap junction F. Hemidesmosome E. Focal adhesion Dr Clemens Kiecker Topic title: Cell types and subcellular structures Desmosomes and hemidesomosomes in the electron microscope 9 http://www.columbia.edu/itc/hs/medical/sbpm_histology_old/lab/lab11_micrograph.html 1. Pairs of dark, disk/button-like structures at cell-cell contacts Cell 1 Cell 2 Garrod et al. J Cell Sci. 2005 118:5743-54 Bars, 100 nm Borradori and Sonnenberg. J Invest Dermatol. 1999 112:411-8 2. Something looking like half-desmosomes at cell-ECM interface Cell ECM https://www.dictionary.com desmo- Greek desmos "bond fastening chain -some Greek sma body = Desmosomes hemi- Greek hmi- half = Hemidesmosomes Cell 1 Cell 2 Dr Clemens Kiecker Topic title: Cell types and subcellular structures (Hemi)desomosomes are linked to intermediate filaments 10 Desmosome Hemidesmosome Dr Clemens Kiecker Topic title: Cell types and subcellular structures The approximate scale of these structures 11 A hemidesmosome ~100 nm wide A desmosome ~500 nm high A cell ~20 m wide Array of hemidesmosomes at cell bottom Dr Clemens Kiecker Topic title: Cell types and subcellular structures Intermediate filaments provide support against mechanical stress 12 Epidermolysis bullosa (mutations in IF or desmosomal factors) Pemphigus (autoantibodies against desmosomes) Has C and Bruckner-Tuderman L. Annu Rev Genomics Hum Genet. 2014;15:245-68. Kasperkiewicz et al. 2017, Nat Rev Dis Primers. 3:17026 Dr Clemens Kiecker Topic title: Cell types and subcellular structures Types of junctional complexes 13 ` A. Tight junction B. Adherens junction C. Desmosome D. Gap junction F. Hemidesmosome E. Focal adhesion Dr Clemens Kiecker Topic title: Cell types and subcellular structures Tight junctions surround the apical surface of epitelial cells 14 Molecular Biology of the Cell Dr Clemens Kiecker Topic title: Cell types and subcellular structures Tight junctions turn epithelia into barriers 15 Claudin (TJ factor) knockout Control Injection of purple dye under skin spreads into upper layers in the Claudin knockout mouse Claudin knockout pups lose weight due to evaporation of water through skin > Furuse et al. 2002, J Cell Biol. 156:1099-111 Dr Clemens Kiecker Topic title: Cell types and subcellular structures Gap junctions couple cells via permeable pores 16 TJ Dispersed in lateral membrane Apical Basal Lateral GJs Gap junctions form fenestrations (pores) that allow small molecules and ions to pass between cells chemical and electrical coupling Dr Clemens Kiecker Topic title: Cell types and subcellular structures Types of junctional complexes 17 ` A. Tight junction B. Adherens junction C. Desmosome D. Gap junction F. Hemidesmosome E. Focal adhesion Dr Clemens Kiecker Topic title: Cell types and subcellular structures Adherens junctions are linked to the actin cytoskeleton 18 TJ AJ Double headband Apical Basal > Pollard et al. Cell Biology 2e - Elsev Actin-myosin can mediate contractile forces bending of epithelia Dr Clemens Kiecker Topic title: Cell types and subcellular structures Focal adhesions link the actin cytoskeleton to the ECM via integrins 19 Kanchanawong et al. Nature 2010;468:580-584 F. Hemidesmosome E. Focal adhesion Molecular Biology of the Cell Basal lamina Dr Clemens Kiecker Topic title: Cell types and subcellular structures Focal adhesions form transiently during cell movement 20 Focal Adhesions Actin Filaments > https://cellix.imba.oeaw.ac.at/cytoskeleton/actin Focal adhesion dynamics in a migrating hu man cell - YouTube Dr Clemens Kiecker Topic title: Cell types and subcellular structures Discovery of the first cell adhesion molecule 21 Masatoshi Takeichi: re- investigated dissociation ofamphibian embryonics (Johannes Holtfreter) Carnegie Institution , Baltimore, US Kyoto University, Japan > (Photo taken in 1969) EDTA sequesters Ca 2+ Dr Clemens Kiecker Topic title: Cell types and subcellular structures Cadherins are Ca 2+ -dependent adhesion molecules 22 Dr Clemens Kiecker Topic title: Cell types and subcellular structures Other types of junctions not covered today > 23 ` A. Tight junction B. Adherens junction C. Desmosome D. Gap junction F. Hemidesmosome E. Focal adhesion Selectin-based adhesion of white blood cells in vessels (leukocyte rolling) Neuronal synapse Plasmodesma (= plant gap junction) Septate junctions (= tight junctions in invertebrates) etc. etc. Dr Clemens Kiecker Topic title: Cell types and subcellular structures Cancer metastasis is intricately linked to cell adhesion 24 Thank you for your attention [email protected] Kings College London. All rights reserved