Involvement of the heterodimeric interface region of the nucleotide binding domain-2 (NBD2) in the CFTR quaternary structure and membrane stability

Biochim Biophys Acta. 2015 Oct;1853(10 Pt A):2420-31. doi: 10.1016/j.bbamcr.2015.06.003. Epub 2015 Jun 14.

Abstract

The cystic fibrosis transmembrane conductance regulator (CFTR) is the only member of the ATP-binding cassette (ABC) superfamily that functions as a chloride channel. The predicted structure of CFTR protein contains two membrane-spanning domains (MSDs), each followed by a nucleotide binding domain (NBD1 and NBD2). The opening of the Cl- channel is directly linked to ATP-driven tight dimerization of CFTR's NBD1 and NBD2 domains. The presence of a heterodimeric interfaces (HI) region in NBD1 and NBD2 generated a head to tail orientation necessary for channel activity. This process was also suggested to promote important conformational changes in the associated transmembrane domains of CFTR, which may impact the CFTR plasma membrane stability. To better understand the role of the individual HI region in this process, we generated recombinant CFTR protein with suppressed HI-NBD1 and HI-NBD2. Our results indicate that HI-NBD2 deletion leads to the loss of the dimerization profile of CFTR that affect its plasma membrane stability. We conclude that, in addition to its role in Cl- transport, HI-NBD2 domain confers membrane stability of CFTR by consolidating its quaternary structure through interactions with HI-NBD1 region.

Keywords: CFTR; Cystic fibrosis; Dimerization; Membrane stability; NBD2; Quaternary structure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cell Membrane / chemistry*
  • Cell Membrane / genetics
  • Cell Membrane / metabolism*
  • Cricetinae
  • Cystic Fibrosis Transmembrane Conductance Regulator / chemistry*
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
  • Humans
  • Protein Stability
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary

Substances

  • CFTR protein, human
  • Cystic Fibrosis Transmembrane Conductance Regulator