Be part of, as a play

• One of the proteins into which actomyosin can be split
• Muscle protein
• " . . . ___ the living Present!": Longfellow
• Words before self-defense
• Be part of the cast of
• Globulin in muscles
• Can exist in either a globular or a fibrous form
• Form the cast of
• Perform as a play

Wiktionary Word definitions in Wiktionary
n. 1 (context protein uncountable English) A globular structural protein that polymerizes in a helical fashion to form an actin filament (or microfilament). 2 (context protein countable English) One of the six isoforms of actin.