Proteomics Shows Hsp70 Does Not Bind Peptide Sequences Indiscriminately in Vivo

Exp Cell Res. 2004 Jul 1;297(1):108-17. doi: 10.1016/j.yexcr.2004.02.030.

Abstract

Heat shock protein 70 (Hsp70) binds peptide and has several functions that include protein folding, protein trafficking, and involvement with immune function. However, endogenous Hsp70-binding peptides had not previously been identified. Therefore, we eluted and identified several hundred endogenously bound peptides from Hsp70 using liquid chromatography ion trap mass spectrophotometry (LC-ITMS). Our work shows that the peptides are capable of binding Hsp70 as previously described. They are generally 8-26 amino acids in length and correspond to specific regions of many proteins. Through computationally assisted analysis of peptides eluted from Hsp70 we determined variable amino acid sequences, including a 5 amino acid core sequence that Hsp70 favorably binds. We also developed a computer algorithm that predicts Hsp70 binding within proteins. This work helps to define what peptides are bound by Hsp70 in vivo and suggests that Hsp70 facilitates peptide selection by aiding a funneling mechanism that is flexible but allows only a limited number of peptides to be processed.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Algorithms*
  • Amino Acid Motifs / physiology*
  • Amino Acid Sequence / physiology
  • Animals
  • Binding Sites / physiology
  • Cell Line
  • Chromatography, Liquid
  • HSP70 Heat-Shock Proteins / chemistry
  • HSP70 Heat-Shock Proteins / metabolism*
  • Mass Spectrometry
  • Mice
  • Models, Molecular
  • Molecular Weight
  • Peptides / chemistry
  • Peptides / metabolism*
  • Protein Binding / physiology
  • Proteomics / methods*

Substances

  • HSP70 Heat-Shock Proteins
  • Peptides