Answer:
b. Integrins
Explanation:
Integrins are a family of plasma membrane proteins. These proteins are involved in the process of signaling between the cell interior and the extracellular matrix. Integrins are heterodimeric proteins and have two different subunits called alpha and beta which are anchored to the plasma membrane by a transmembrane helix.
Integrins have binding sites for many extracellular macromolecules as they also serve as receptors and signal transducers. Integrin gene codes for the beta subunit of adhesion molecule of leucocytes which is also called CD18. Mutation in this integrin gene results in leukocyte adhesion deficiency in humans.
