Possible Clues:

• Have a role
• Words before good faith
• Join the cast of, as a movie
• Words with ''good faith'' or ''self-defense''
• Words before "self-defense" or "good faith"
• It's mostly serving as a protein
• What can affect muscles? A cold can
• Endlessly functioning as protein
• Be a part of, as a picture
• Cellular protein in microfilaments