True about integrin is –
**Core Concept**
Integrins are a family of transmembrane receptors that play a crucial role in cell adhesion and signaling. They are heterodimeric proteins composed of alpha and beta subunits, which interact with extracellular matrix proteins, such as laminin and collagen, and intracellular signaling molecules.
**Why the Correct Answer is Right**
Integrins are involved in various cellular processes, including cell migration, proliferation, and differentiation. They mediate cell adhesion to the extracellular matrix through interactions with specific ligands, such as RGD (arginine-glycine-aspartate) sequences. Integrin signaling is also crucial for platelet aggregation and activation, which is essential for blood clotting. The correct answer is related to the mechanism of integrin-mediated cell adhesion.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe a key function of integrins. Integrins are not primarily involved in neurotransmission.
**Option B:** This option is incorrect because it is a characteristic of adhesion molecules, but not a defining feature of integrins. Integrins are heterodimeric receptors, but this option does not accurately describe their function.
**Option C:** This option is incorrect because it is a characteristic of selectins, not integrins. Selectins are a family of adhesion molecules that mediate leukocyte rolling and migration.
**Clinical Pearl / High-Yield Fact**
Integrins play a critical role in the development and progression of various diseases, including cancer, cardiovascular disease, and inflammatory disorders. Understanding the function and regulation of integrins is essential for the development of targeted therapies.
**Correct Answer:** D