Final answer:
Spectrin is the cytoskeletal protein that supports the plasma membrane in eukaryotic cells, helping with cell shape maintenance and plasma membrane stability.
Step-by-step explanation:
The cytoskeletal protein that lines the intracellular side of the plasma membrane in eukaryotic cells is spectrin. The cytoskeleton is made up of a network of long, thin protein fibers that include microtubules, intermediate filaments, and microfilaments. Spectrin is a cytoskeletal protein that helps to maintain the shape of the cell by forming a network along the cytoplasmic side of the plasma membrane.
This network provides structural support, contributing to the elasticity and stability of the plasma membrane. Another important function of spectrin is to help organize the lipid bilayer and associated proteins within the membrane, allowing for better mechanical support and cell's resilience during deformation.