Metamorphic response of the CLIC1 chloride intracellular ion channel protein upon membrane interaction

Sophia C. Goodchild, Michael W. Howell, Dene R. Littler, Ramya A. Mandyam, Kenneth L. Sale, Michele Mazzanti, Samuel N. Breit, Paul M G Curmi, Louise J. Brown

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

A striking feature of the CLIC (chloride intracellular channel) protein family is the ability of its members to convert between a soluble state and an integral membrane channel form. Direct evidence of the structural transition required for the CLIC protein to autonomously insert into the membrane is lacking, largely because of the challenge of probing the conformation of the membrane-bound protein. However, insights into the CLIC transmembrane form can be gained by biophysical methods such as fluorescence resonance energy transfer (FRET) spectroscopy. This approach was used to measure distances from tryptophan 35, located within the CLIC1 putative N-domain transmembrane region, to three native cysteine residues within the C-terminal domain. These distances were computed both in aqueous solution and upon the addition of membrane vesicles. The FRET distances were used as constraints for modeling of a structure for the CLIC1 integral membrane form. The data are suggestive of a large conformational unfolding occurring between the N- and C-domains of CLIC1 upon interaction with the membrane. Consistent with previous findings, the N-terminal domain of CLIC1 is likely to insert into the lipid bilayer, while the C-domain remains in solution on the extravesicular side of the membrane.

Original languageEnglish
Pages (from-to)5278-5289
Number of pages12
JournalBiochemistry
Volume49
Issue number25
DOIs
Publication statusPublished - 29 Jun 2010

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