Decrease in heart peptide initiation during head-down tilt may be modulated by HSP-70

V. Menon, J. Yang, Z. Ku, Donald Thomason

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

This study examines the mechanism of the rapid decrease in cardiac muscle protein synthesis during rodent hindlimb non-weight bearing. Polysomes isolated from rat hearts 8 h after suspension show less RNA in the polysome pool and a shift in polysome size toward fewer ribosomes per mRNA; 18 h after suspension, the size shift persists, but the amount of RNA in the polysome pool returns to control values. These data are consistent with a decrease in the rate of initiation of protein synthesis. At both 8 and 12 h of suspension, the cardiac polysomes show a 78 and 93% increased association with the nascent polypeptide chaperone protein 70-kDa heat-shock cognate/heat-shock protein (HSC/HSP-70), respectively, that persists after 7 days of non-weight bearing. Because the dissociation of HSC/HSP-70 from unfolded protein can be modulated by ATP, we measured the adenosine nucleotide pools and found a 53% decrease in ATP levels after 18 h of suspension. We propose a mechanism in which a shift of HSC/HSP-70 to the nascent polypeptide indirectly inhibits protein synthesis initiation.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume268
Issue number6 37-6
StatePublished - 1995

Fingerprint

Head-Down Tilt
Polyribosomes
Suspensions
Bearings (structural)
Peptides
HSC70 Heat-Shock Proteins
Adenosine Triphosphate
RNA
Proteins
Muscle Proteins
Heat-Shock Proteins
Protein Unfolding
Adenosine
Rats
Hindlimb
Ribosomes
Nucleotides
Association reactions
Rodentia
Myocardium

All Science Journal Classification (ASJC) codes

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

Cite this

Decrease in heart peptide initiation during head-down tilt may be modulated by HSP-70. / Menon, V.; Yang, J.; Ku, Z.; Thomason, Donald.

In: American Journal of Physiology - Cell Physiology, Vol. 268, No. 6 37-6, 1995.

Research output: Contribution to journalArticle

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