Final answer:
The family of integral membrane proteins composed of two membrane-spanning chains (alpha and beta) responsible for cell adhesion to the extracellular matrix is known as integrins. These transmembrane proteins are part of complex structures that connect cells to their surrounding environment and facilitate essential cellular functions.
Step-by-step explanation:
The integral membrane protein family that is made of two membrane-spanning chains (α and β) and is involved in attaching cells to their extracellular microenvironment is known as integrins. These transmembrane proteins span the entire plasma membrane and play a crucial role in the interaction between a cell and the extracellular matrix. With their hydrophobic regions intermingling with the inner part of the lipid bilayer and hydrophilic regions protruding to either the exterior or the interior of the cell, integrins facilitate a variety of cellular responses, including cell adhesion to the extracellular matrix, as well as signaling across the cell membrane.
Integrins, being integral proteins, are differ from peripheral proteins that are more loosely attached to the membrane, and do not span the lipid bilayer. Integrins form part of a larger network that includes both the extracellular matrix components, like collagen, and cytoplasmic proteins, such as talin, that connect to the actin cytoskeleton within the cell. This complex interface allows not only for physical support but also cellular communication, affecting a range of cellular activities, including cell migration, proliferation, and survival, which are vital for tissue maintenance and repair. Focal adhesions are one example of the complex assemblies involving integrins, linking the extracellular environment to the cell's internal structure.