LRP130, a single-stranded DNA/RNA-binding protein, localizes at the outer nuclear and endoplasmic reticulum membrane, and interacts with mRNA in vivo

Biochem Biophys Res Commun. 2004 May 7;317(3):736-43. doi: 10.1016/j.bbrc.2004.03.103.

Abstract

LRP130 (also known as a LRPPRC) is an RNA and single-stranded DNA-binding protein, and recently identified as a candidate gene responsible for the Leigh syndrome, a French-Canadian type cytochrome c oxidase deficiency. However, the biological function of LRP130 still remains largely unresolved. In the present study, we found that the C-terminal half of the mouse LRP130 located within a 120 amino acid sequence (a.a. 845-964) binds to synthetic RNA homopolymers, poly(G), poly(U), and poly(C), as well as r(CUGCC)(6). Assessment of the subcellular localization indicated both nuclear/endoplasmic reticulum (ER) and mitochondrial fractions to be positive. To further analyze the subcellular localization of LRP130, a nuclear/ER fraction was fractionated into the nucleoplasm (NP) and nuclear envelope (NE)/ER, and the latter was further separated into outer nuclear membrane (ONM)/ER and inner nuclear membrane (INM) by treatment with Triton X-100. LRP130 was detectable in all three fractions, and the distribution pattern was in good accordance with that known for ONM/ER proteins. Interestingly, immunostaining of HeLa cells demonstrated nuclear rim staining of LRP130, specifically at the outside of the NE and also at ER, and association of LRP130 with poly(A)(+) RNA was restricted only to the ONM/ER fraction. Overexpression of full-length mouse LRP130 fused with EGFP resulted in nuclear accumulation of poly(A)(+) RNA in HeLa cells. Taking all these results together, it is suggested that LRP130, a novel type of RNA-binding protein, associates with mRNA/mRNP complexes at the outside of NE and ER, and plays a role in control of mRNA metabolisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Nucleus / metabolism*
  • Endoplasmic Reticulum / metabolism*
  • HeLa Cells
  • Humans
  • Intracellular Membranes / metabolism*
  • Mice
  • Microscopy, Fluorescence
  • Neoplasm Proteins / metabolism*
  • RNA, Messenger / metabolism*
  • RNA-Binding Proteins / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Subcellular Fractions / metabolism

Substances

  • LRPPRC protein, human
  • Lrpprc protein, mouse
  • Neoplasm Proteins
  • RNA, Messenger
  • RNA-Binding Proteins