Final Answer:
Integrins bind on the outer side of the plasma membrane through a process called extracellular binding. This involves the interaction of integrin extracellular domains with specific ligands present in the extracellular matrix, facilitating cellular adhesion and signaling.
Step-by-step explanation:
Integrins are transmembrane proteins that play a crucial role in cell adhesion and signal transduction. The process of how integrins bind on the outer side of the plasma membrane is known as extracellular binding.
The extracellular domains of integrins are located outside the cell, and they interact with ligands present in the extracellular matrix (ECM). The binding of integrins to ECM components, such as fibronectin or collagen, is specific and facilitates the attachment of cells to the surrounding matrix. This interaction is essential for various cellular processes, including cell migration, proliferation, and differentiation.
The extracellular binding of integrins is a dynamic process regulated by conformational changes in the integrin structure. Integrins can exist in different conformations, including an inactive bent conformation and an active extended conformation. The binding of ligands induces conformational changes in integrins, leading to increased affinity for ligands and strengthening the connection between the cell and the ECM.
This dynamic interaction allows cells to respond to their environment and modulate their behavior accordingly. In summary, the outer side binding of integrins involves extracellular domains interacting with specific ligands in the extracellular matrix, contributing to the regulation of cellular adhesion and signaling.