|
Substrate adhesion molecules
|
|
Substrate adhesion molecules (SAMs), also known as cell-substrate adhesion molecules, cell-substratum adhesion molecules, substratum adhesion molecules, or cell-matrix molecules, are single-pass membrane proteins characterized by their role in binding cells to the extracellular matrix (ECM). As it is commonly understood that individual members of this family bind ECM elements, publications often forego the SAM classification and will instead refer to these proteins under the broader classification for proteins involved in adhesion, cell adhesion molecules. Examples * Integrins * CD44 Structure The intracellular side will be anchored to the cytoskeleton (actin, in the case of integrins), while the substrate side will anchor to the ECM. Integrins have two subunits, an α and a β. Both bind to the ECM on the substrate side, which activates the actin-binding activity of the β unit on the intracellular side. This forms what is called a focal adhesion, which enables external activity in the extracellular matrix to affect the shape and movement of the cell. CD44 only has one subunit, with a long substrate-side N-terminal head and a short intracellular tail. The extracellular domain can bind many different molecules, including those composing the ECM. The intracellular domain can then bind with various effector proteins, including actin. CD44 is primarily involved in signaling. Relevance in Biology Neuronal Morphogenesis SAMs play a key role in neuronal morphogenesis. Integrin organizes actin to aid in synaptic stability, synaptic plasticity, and dendritic stability on the dendritic end of a neuron. On the axonal end, focal adhesions are formed to aid the axon terminal in locomotion towards the proper location. Cancer Markers CD44 is a prominent cancer marker because it plays many important roles in cancer pathology. It can trigger the digestion of the ECM to allow metastasis, trigger angiogenesis, inhibit the P53 apoptosis monitoring system, and, when bound to hyaluronic acid, trigger the MAPK cascade to promote proliferation. 
|
| < Prev | Next > |
|---|
Main Menu
| Home |
| Articles |
| Search |
| Submit Article |
| Contact Us |
| Donate to Wikibin |
