Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- Read me first …
- Glossary
- Dedication
- Introduction: A disease for every gene?
- I From molecular biology to human genetics
- II From molecular genetics to human biochemistry
- 6 Nutrition and energy
- 7 Membranes and channels
- 8 Cell-surface receptors and antigen recognition
- 9 Adhesion molecules and the extracellular matrix
- 10 Cytoskeletal proteins and molecular motors
- III From molecular biochemistry to human cell biology
- IV From molecular cell biology to human physiology
- V From molecular physiology to human molecular biology
- Index
8 - Cell-surface receptors and antigen recognition
Published online by Cambridge University Press: 01 June 2011
- Frontmatter
- Contents
- Preface
- Acknowledgements
- Read me first …
- Glossary
- Dedication
- Introduction: A disease for every gene?
- I From molecular biology to human genetics
- II From molecular genetics to human biochemistry
- 6 Nutrition and energy
- 7 Membranes and channels
- 8 Cell-surface receptors and antigen recognition
- 9 Adhesion molecules and the extracellular matrix
- 10 Cytoskeletal proteins and molecular motors
- III From molecular biochemistry to human cell biology
- IV From molecular cell biology to human physiology
- V From molecular physiology to human molecular biology
- Index
Summary
To communicate at the cellular level, multicellular organisms must have ways of making intercellular contact. The human body contains about ten trillion (1013) cells (actually, it contains far more than that – but most of those additional cells are bacteria!). All these cells need to talk to each other, and to this end have evolved elaborate networks of cellsurface recognition and signaling molecules as described below.
Cell-surface receptors
Extracellular events trigger intracellular signaling
The surface of the plasma membrane is studded with proteins inserted into the bilayer which connect the extracellular space with the cytoplasm. This network of integral membrane proteins enables cells to sense what happens around them. Transmembrane proteins are stabilized by the insertion of a hydrophobic domain(s) into the amphipathic lipid environment of the membrane bilayer (Figure 8.2): since there are no hydrogen donors or acceptors in the membrane, the hydrogen bonding of transmembrane domains needs to be fully satisfied within the main chain of the peptide itself. Membrane-spanning domains fulfill this requirement for internal hydrogen bonding by adopting repeating main chain secondary structures of bundled α-helices or β-barrels in the presence of apolar side chains. Bacteria have exploited this hydrophobic effect by producing pore-forming toxins such as α-hemolysin, which insert tenaciously into human cell membranes via their nonpolar oligomeric β-barrel structures.
- Type
- Chapter
- Information
- Human Molecular BiologyAn Introduction to the Molecular Basis of Health and Disease, pp. 193 - 208Publisher: Cambridge University PressPrint publication year: 2002