- 1 Introduction
- 2 Objectives
- 3 History
- 4 Why Adhesion?
- 5 Types of Adhesion
- 6 Adhesive Functions
- 7 Adhesion Characteristics
- 8 Types of Adhesion Molecules
- 9 Selectins
- 10 Integrins
- 11 Cell Junction Types
- 12 Junctions Overview - Typical Epithelia
- 13 Extracellular Matrix
- 14 Integrins
- 15 Abnormalities
- 16 References
- 17 Working Area
- 18 2017 Course Content
Lets stick together!
This lecture introduces the concept of cell adhesion. Unicellular organisms use to adhere to the environment, nutrition or pathogenesis. Multicellular organisms require adhesion for cells to adhere to each other and the extracellular matrix. Cell adhesion occurs through specific cellular specializations and molecules and has both static and dynamic functions. This topic will be revisited in lectures on extracellular matrix, cell cytoskeleton and signalling.
2017 Lecture Announcement
To start audio, click the start triangle above.
| Due to a teaching double booking announced in the Tuesday Practical class, I am providing an earlier audio recording of the adhesion lecture along with the current lecture information on this page. Note that you can start the audio on the left and then scroll down the page to complete the lecture. This content will still form part of the examinable material for the final theory exam. (Play audio | MP3 file for download)
Note the Thursday lecture on Mitochondria will be presented as scheduled.
See also ANAT3231 Group Projects 2011
Below are some example historical research finding related to cell junctions from the JCB Archive. (Students note that the history is provided only as background for the lecture topic)
1963 Defining junctional complexes A mess of nomenclature is sorted out by Marilyn Farquhar and George Palade, who use superb microscopy to define three of the four major types of cell–cell junctions in the polarized epithelial cells of vertebrates.
1967 Defining gap junctions Jean-Paul Revel and Morris Karnovsky unite the fields of adhesion and intercellular current transfer around a distinct, structural correlate called the gap junction.
1967 Endothelial tight junctions form the blood–brain barrier What is the cellular correlate of the so called blood-brain barrier? Thomas Reese and Morris Karnovsky find that it is the junctions between endothelial cells in the brain vasculature. Their discovery comes thanks to three factors: high resolution electron microscopy; the development of sensitive tracer methods; and a fortuitous lunch date.
1977 The sticky business of discovering cadherins A change in the recipe for a trypsin solution allows Masatoshi Takeichi to distinguish calcium-dependent adhesion.
1984 Sticking it out with tight junctions With persistence and a species change, tight junction proteins are isolated.
- Adhesion refers to “stickiness”
- Evolution of multicellular organisms developed specialized cells and tissues
- Embryonic development also allows differentiation of different cell/tissue types
- Interaction between cell-cell and cell-extracellular matrix by specific contacts
- Adhesion strength can be strong or weak as well as dynamically altered (as in migrating cells)
- Note the Cell Biology definition is different from the Clinical term
- Clinical term “adhesions” bands of scar-like tissue forming between two surfaces inside the body
- Prokaryotes adhesion molecules usually termed "adhesins"
- occur on pili (fimbriae), flagellae, or the cell surface
- adhesion first step in colonization
- express multiple adhesion molecules for nutrition, migration and pathogenesis
- malarial parasite (Plasmodium falciparum) to bind to
- Maintains body form and structure
- Tissues organized during development
- Can be used for cell migration
- Cell signalling alteration in disease
- Large number of different transmembrane proteins forming cell - cell and cell - extracellular matrix junctions
- Link to cell cytoskeleton or form communication channels between cells
- Cell adhesion involved in signaling processes
Types of Adhesion
- Cell-extracellular matrix
- Transmembrane glycoproteins
- Normally permanent
- Except migrating cells and embryonic
- Changes with development
- Cells loose adhesion when mature or disease conditions. (see Erythrocytes, cancer)
Types of Adhesion Molecules
Each type of junction involves specific adhesion molecules embedded in the cell plasma membrane.
- Immunoglobulin Superfamily
See additional information on interns below.
Cell Junction Types
- cell anchored to extracellular matrix (Hemi = half)
- Present in tissues subject to shear or lateral stress
- microfilaments (MF) anchor the plaque that occurs under the membrane of each cell
- plaques not as dense also occur as hemi-form
- heart muscle, layers covering body organs, digestive tract
- transmembrane proteins
- Discovered by R.L. Wood 1959
- found in invertebrate tissues - adhesion, sealing, communication
- vertebrates do not have these junctions
- septa = walls, regularly spaced cross bars 15-17 nm
Electron Micrograph Filtered Image of Two Connexons
- Discovered by A. Rustom and H.-H. Gerdes in 2004
- allowing direct communication between cells
- connecting cells at a distance of up to several cell diameters
- tubes with a diameter of 50-200 nm
Junctions Overview - Typical Epithelia
Mammals have genes for 18 alpha and eight beta integrins Role in cell adhesion to extracellular matrix (ECM) basement membranes Induction of cell polarization by adhesion Cell migration through ECM Mainly receptors for ECM proteins Fibronectin, laminin, collagen Some heterotypic binding Ig superfamily Interact with cell cytoskeleton signalling
- pemphigus and bullous impetigo - antibodies made against one of their own desmosomal cadherin proteins
- antibodies bind to and disrupt the desmosomes that hold together skin epithelial cells
- severe skin blistering, leakage of body fluids
Arrhythmogenic right-ventricular cardiomyopathy (ARVC)
- not the cause but transformed cells loose adhesion, able to "break away" and spread (metastasis).
Essential Cell Biology
- Chapter 19 Tissues Epithelial sheets and Cell-Cell Junctions p606
Molecular Biology of the Cell
Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter New York and London: Garland Science; c2002
- Molecular Biology of the Cell 4th ed. - V. Cells in Their Social Context Chapter 19. Cell Junctions, Cell Adhesion, and the Extracellular Matrix
- Cell Junctions
Molecular Cell Biology
Lodish, Harvey; Berk, Arnold; Zipursky, S. Lawrence; Matsudaira, Paul; Baltimore, David; Darnell, James E. New York: W. H. Freeman & Co.; c1999
- Molecular Cell Biology - Chapter 22. Integrating Cells into Tissues 22.1. Cell-Cell Adhesion and Communication
- Cell-Cell Adhesion and Communication
- Cell-Matrix Adhesion
The Cell- A Molecular Approach
Cooper, Geoffrey M. Sunderland (MA): Sinauer Associates, Inc.; c2000
- The Cell - A Molecular Approach - III. Cell Structure and Function Chapter 12 The Cell Surface
- Cell-Cell Interactions
- Cell Adhesion Molecules
Search Online Textbooks
- "cell junctions" Molecular Biology of the Cell | Molecular Cell Biology | The Cell- A molecular Approach | Bookshelf
- PubMed is a service of the U.S. National Library of Medicine that includes over 18 million citations from MEDLINE and other life science journals for biomedical articles back to 1948. PubMed includes links to full text articles and other related resources. PubMed
- PubMed Central (PMC) is a free digital archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health (NIH) in the National Library of Medicine (NLM) allowing all users free access to the material in PubMed Central. PMC
- Online Mendelian Inheritance in Man (OMIM) is a comprehensive compendium of human genes and genetic phenotypes. The full-text, referenced overviews in OMIM contain information on all known mendelian disorders and over 12,000 genes. OMIM
- Entrez is the integrated, text-based search and retrieval system used at NCBI for the major databases, including PubMed, Nucleotide and Protein Sequences, Protein Structures, Complete Genomes, Taxonomy, and others Entrez
- "cell junctions" PubMed reviews | PubMed all articles | PMC reviews | PMC all articles | OMIM | Entrez all databases
- Tight junctions/adherens junctions: basic structure and function. Niessen CM. J Invest Dermatol. 2007 Nov;127(11):2525-32. Review.. PMID: 17934504
- The tight junction: a multifunctional complex. Schneeberger EE, Lynch RD. Am J Physiol Cell Physiol. 2004 Jun;286(6):C1213-28. Review. PMID: 15151915 Am J Physiol Cell Physiol
- The desmosome and pemphigus. Waschke J. Histochem Cell Biol. 2008 Jul;130(1):21-54. Epub 2008 Apr 3. Review. PMID: 18386043
- Tunneling Nanotubes. Rustom A. Ann N Y Acad Sci. 2009 Oct;1178:126-39. Review. PMID: 19845633
There is also a gallery of all images added sorted by date New Images (the search option will only search by image file name).
2017 Course Content
Lectures: Cell Biology Introduction | Cells Eukaryotes and Prokaryotes | Cell Membranes and Compartments | Cell Nucleus | Cell Export - Exocytosis | Cell Import - Endocytosis | Cytoskeleton Introduction | Cytoskeleton - Microfilaments | Cytoskeleton - Microtubules | Cytoskeleton - Intermediate Filaments | Cell Mitochondria | Cell Junctions | Extracellular Matrix 1 | Extracellular Matrix 2 | Cell Cycle | Cell Division | Cell Death 1 | Cell Death 2 | Signal 1 | Signal 2 | Stem Cells 1 | Stem Cells 2 | Development | 2017 Revision
Dr Mark Hill 2015, UNSW Cell Biology - UNSW CRICOS Provider Code No. 00098G