| − | '''Actin''' is a [[helical]] [[protein]] that forms [[microfilament|microfilaments]]. It is an essential element of the [[cytoskeleton]] of a [[biological cell]]. | + | '''Actin''' is a [[helical]] [[protein]] that forms [[microfilament|microfilaments]]. It is an essential element of the [[cytoskeleton]] of a [[biological cell]]. Actin binds GTP, allowing the filaments to extend and contract rapidly, with a force of up to 200 piconewtons. |