The degeneracy of the code is not uniform. Whereas methionine and tryptophan have single codons, for example, three amino acids (Arg, Leu, Ser) have six codons, five amino acids have four, isoleucine has three, and nine amino acids have two.

TLS Online TPP Program

#Id: 1419

#Unit 4. Cell Communication and Cell Signaling

An integrin molecule is composed of two noncovalently associated transmembrane glycoprotein subunits called α and β.

TLS Online TPP Program

#Id: 1420

#Unit 4. Cell Communication and Cell Signaling

Integrins function as transmembrane linkers (integrators) between the extracellular matrix and the actin cytoskeleton.

TLS Online TPP Program

#Id: 1421

#Unit 4. Cell Communication and Cell Signaling

Integrins bind extracellular matrix (ECM) glycoproteins, 1. Laminins  

2. Collagens 

3. Fibronectin

4. Vitronectin

TLS Online TPP Program

#Id: 1422

#Unit 4. Cell Communication and Cell Signaling

Fibronectin binds to integrin through an RGD motif.

TLS Online TPP Program

#Id: 1423

#Unit 4. Cell Communication and Cell Signaling

The binding of integrins to their ligands depends on extracellular divalent cations(Ca+2 & Mg+2).

TLS Online TPP Program

#Id: 1424

#Unit 4. Cell Communication and Cell Signaling

The α subunit of each integrin is the primary determinant of its extracellular ligand specificity.