Final answer:
The proteins that connect the cell's cytoskeleton and the extracellular matrix through the plasma membrane are known as integrin proteins. They play a key role in cell signaling and structural integrity.
Step-by-step explanation:
The proteins that extend from the cytoskeleton within the cell, through the plasma membrane, and into the extracellular matrix are known as integrin proteins. Integrins are crucial for connecting the extracellular matrix to the cytoskeleton, which aids in cell signaling and maintaining the structural integrity and shape of cells. Integral proteins, such as integrins, span the membrane and are directly involved in communication and bonding between cells and their surroundings. The extracellular matrix, which consists of a network of proteins and carbohydrates, attaches to these integrin proteins. Additionally, integrins are involved in transmitting signals into the cell that can affect cellular activities, including the transcription of DNA, to modify protein production.