Interaction of two multifunctional proteins. Heterogeneous nuclear ribonucleoprotein K and Y-box-binding protein

J Biol Chem. 2000 May 19;275(20):15498-503. doi: 10.1074/jbc.275.20.15498.

Abstract

The heterogeneous nuclear ribonucleoprotein (hnRNP) K, a component of the hnRNP particles, appears to be involved in several steps of regulation of gene expression. To gain insight into mechanisms of K protein action, we performed two-hybrid screens using full-length hnRNP K as a bait. Several novel protein partners were identified, including Y-box-binding protein (YB-1), splicing factors 9G8 and SRp20, DNA-methyltransferase, hnRNP L, and hnRNP U. In vitro binding studies and co-immunoprecipitation from cellular extracts provided evidence for direct interaction between hnRNP K and YB-1. Two distinct domains in YB-1 were responsible for binding to K protein. Each protein was able to transactivate transcription from a polypyrimidine-rich promoter; however, this effect was reduced when K and YB-1 proteins were coexpressed suggesting a functional interaction between these two proteins.

Publication types

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

MeSH terms

  • Animals
  • Binding Sites
  • CCAAT-Enhancer-Binding Proteins*
  • Cloning, Molecular
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Embryo, Mammalian
  • Gene Library
  • HeLa Cells
  • Heterogeneous-Nuclear Ribonucleoprotein K
  • Heterogeneous-Nuclear Ribonucleoprotein L
  • Heterogeneous-Nuclear Ribonucleoprotein U
  • Heterogeneous-Nuclear Ribonucleoproteins
  • Humans
  • Jurkat Cells
  • Mice
  • NFI Transcription Factors
  • Nuclear Proteins
  • RNA-Binding Proteins / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Ribonucleoproteins / chemistry
  • Ribonucleoproteins / genetics
  • Ribonucleoproteins / metabolism*
  • Transcription Factors / metabolism
  • Transfection
  • Y-Box-Binding Protein 1

Substances

  • CCAAT-Enhancer-Binding Proteins
  • DNA-Binding Proteins
  • Heterogeneous-Nuclear Ribonucleoprotein K
  • Heterogeneous-Nuclear Ribonucleoprotein L
  • Heterogeneous-Nuclear Ribonucleoprotein U
  • Heterogeneous-Nuclear Ribonucleoproteins
  • NFI Transcription Factors
  • Nuclear Proteins
  • RNA-Binding Proteins
  • Recombinant Proteins
  • Ribonucleoproteins
  • Transcription Factors
  • Y-Box-Binding Protein 1
  • YBX1 protein, human