In addition to the actin and myosin components that constitute the sarcomere, skeletal muscle fibers also contain two other important regulatory proteins, troponin and tropomyosin, that are necessary for muscle contraction to occur.
I tillæg til aktin og myosin-komponenter der er bestanddelene i sarkomerne, indeholder skeletmuskelfibrene også to andre vigtigt regulerende proteiner, troponin og tropomyosin, der er nødvendige for at muskelkontraktion sker.