spectrin

noun

spec·​trin ˈspek-trən 

: a large cytoskeletal protein that is found on the inner cell membrane of red blood cells and that functions especially in maintaining cell shape

The erythrocyte cytoskeleton, which consists primarily of a meshwork of spectrin and actin, controls cell shape and the disposition of protein within the membrane.

—Robert Siman et al., Nature

A number of genetic diseases (hemolytic anemias) characterized by fragile, abnormally shaped erythrocytes have been traced to mutations in ankyrin or spectrin.

—Gerald Karp, Cell and Molecular Biology: Concepts and Experiments, 6th edition