Y-box protein-associated acidic protein (YBAP1/C1QBP) affects the localization and cytoplasmic functions of YB-1

Sci Rep. 2018 Apr 18;8(1):6198. doi: 10.1038/s41598-018-24401-3.

Abstract

The Y-box proteins are multifunctional nucleic acid-binding proteins involved in various aspects of gene regulation. The founding member of the Y-box protein family, YB-1, functions as a transcription factor as well as a principal component of messenger ribonucleoprotein particles (mRNPs) in somatic cells. The nuclear level of YB-1 is well correlated with poor prognosis in many human cancers. Previously, we showed that a Y-box protein-associated acidic protein, YBAP1, which is identical to complement component 1, q subcomponent-binding protein (C1QBP, also called gC1qR, hyaluronan-binding protein 1 [HABP1] or ASF/SF2-associated protein p32), relieves translational repression by YB-1. Here we show that the nuclear localization of YB-1 harboring a point mutation in the cold shock domain was inhibited when co-expressed with YBAP1, whereas cytoplasmic accumulation of the wild-type YB-1 was not affected. We showed that YBAP1 inhibited the interaction between YB-1 and transportin 1. In the cytoplasm, YBAP1 affected the accumulation of YB-1 to processing bodies (P-bodies) and partially abrogated the mRNA stabilization by YB-1. Our results, indicating that YBAP1/C1QBP regulates the nucleo-cytoplasmic distribution of YB-1 and its cytoplasmic functions, are consistent with a model that YBAP1/C1QBP acts as an mRNP remodeling factor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Nucleus / metabolism
  • Cytoplasm / metabolism
  • Gene Expression
  • HeLa Cells
  • Humans
  • Mitochondrial Proteins / chemistry
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Models, Biological
  • Mutation
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Transport
  • RNA Stability
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Y-Box-Binding Protein 1 / chemistry
  • Y-Box-Binding Protein 1 / genetics
  • Y-Box-Binding Protein 1 / metabolism*
  • beta Karyopherins / metabolism

Substances

  • C1QBP protein, human
  • Carrier Proteins
  • Mitochondrial Proteins
  • RNA, Messenger
  • TNPO1 protein, human
  • Y-Box-Binding Protein 1
  • beta Karyopherins