one of the proteins into which actomyosin can be split; can exist in either a globular or a fibrous form
"The scientist examined the muscle tissue under a microscope to observe how actin, one protein that splits from actomyosin and exists in both globular and fibrous forms, interacted with myosin during contraction."
A globular structural protein that polymerizes in a helical fashion to form an actin filament (or microfilament).
"The researcher stained the cell samples with fluorescent markers to visualize how actin assembled into dynamic filaments along the edges of the migrating cells."