Posttranslational incorporation of contractile proteins into myofibrils in a cell-free system. Academic Article uri icon

Overview

abstract

  • The incorporation of newly synthesized protein into myofibrils has been examined in a cell-free system. Myofibrils were added to a reticulocyte lysate after the in vitro translation of muscle-specific poly(A)+RNA. Only a small number of the many synthesized proteins were found to associate with the exogenously added myofibrils. These proteins were all identified as sarcomeric components and had subunit mobilities (Mr) of 200, 140, 95, 86, 43, 38, 35, 25, 23, 20, and 18 kD. The association was rapid (t1/2 less than 15 min) and, for most of the proteins, relatively temperature insensitive. Except for a 43-kD polypeptide, tentatively identified as beta-actin, none of the proteins encoded by brain poly(A)+RNA associated with the myofibrils. When filaments made from purified myosin or actin were used as the "capture" substrates, only thick or thin filament proteins, respectively, were incorporated. Incorporation was substantially reduced when cross-linked myosin filaments were used. These results are compatible with a model in which proteins of the sarcomere are in kinetic equilibrium with homologous proteins in a soluble pool.

publication date

  • August 1, 1988

Research

keywords

  • Muscle Proteins
  • Muscles
  • Myofibrils

Identity

PubMed Central ID

  • PMC2115203

Scopus Document Identifier

  • 0023764056

Digital Object Identifier (DOI)

  • 10.1083/jcb.107.2.587

PubMed ID

  • 3417763

Additional Document Info

volume

  • 107

issue

  • 2