Final answer:
The correct answer is option a and c. Actin and myosin are the proteins associated with focal adhesions, playing a critical role in cell adhesion and signal transduction.
Step-by-step explanation:
The proteins known to be associated with focal adhesions are actin and myosin. These proteins are crucial for the formation and function of focal adhesions, which are complex structures that mediate the attachment of a cell to the extracellular matrix and facilitate signal transduction to the cell's interior. Actin is a key component of the cytoskeleton and is involved in cell movement and stability. It binds to transmembrane adhesion receptors of the integrin family, forming a connection to the extracellular matrix.
Myosin, particularly non-muscle myosin II, is involved in generating the contractile forces necessary for focal adhesion dynamics and is a major constituent of stress fibers that exert tension and facilitate cell motility. Other proteins such as talin, vinculin, and paxillin are also involved in strengthening the linkage between integrins and the actin cytoskeleton.