Identification of amino acid residues lining the pore of a gap junction channel

I. M. Skerrett, J. Aronowitz, J. H. Shin, G. Cymes, E. Kasperek, F. L. Cao, Bruce J Nicholson

Research output: Contribution to journalArticle

73 Citations (Scopus)

Abstract

Gap junctions represent a ubiquitous and integral part of multicellular organisms, providing the only conduit for direct exchange of nutrients, messengers and ions between neighboring cells. However, at the molecular level we have limited knowledge of their endogenous permeants and selectivity features. By probing the accessibility of systematically substituted cysteine residues to thiol blockers (a technique called SCAM), we have identified the pore-lining residues of a gap junction channel composed of Cx32. Analysis of 45 sites in perfused Xenopus oocyte pairs defined M3 as the major pore-lining helix, with M2 (open state) or M1 (closed state) also contributing to the wider cytoplasmic opening of the channel. Additional mapping of a close association between M3 and M4 allowed the helices of the low resolution map (Unger et al., 1999. Science. 283:1176-1180) to be tentatively assigned to the connexin transmembrane domains. Contrary to previous conceptions of the gap junction channel, the residues lining the pore are largely hydrophobic. This indicates that the selective permeabilities of this unique channel class may result from novel mechanisms, including complex van der Waals interactions of permeants with the pore wall, rather than mechanisms involving fixed charges or chelation chemistry as reported for other ion channels.

Original languageEnglish (US)
Pages (from-to)349-359
Number of pages11
JournalJournal of Cell Biology
Volume159
Issue number2
DOIs
StatePublished - Oct 28 2002
Externally publishedYes

Fingerprint

Gap Junctions
Amino Acids
Connexins
Xenopus
Ion Channels
Sulfhydryl Compounds
Oocytes
Cysteine
Permeability
Ions
Food

Keywords

  • Accessibility
  • Connexin32
  • Pore lining
  • SCAM
  • Xenopus oocyte expression

ASJC Scopus subject areas

  • Cell Biology

Cite this

Skerrett, I. M., Aronowitz, J., Shin, J. H., Cymes, G., Kasperek, E., Cao, F. L., & Nicholson, B. J. (2002). Identification of amino acid residues lining the pore of a gap junction channel. Journal of Cell Biology, 159(2), 349-359. https://doi.org/10.1083/jcb.200207060

Identification of amino acid residues lining the pore of a gap junction channel. / Skerrett, I. M.; Aronowitz, J.; Shin, J. H.; Cymes, G.; Kasperek, E.; Cao, F. L.; Nicholson, Bruce J.

In: Journal of Cell Biology, Vol. 159, No. 2, 28.10.2002, p. 349-359.

Research output: Contribution to journalArticle

Skerrett, IM, Aronowitz, J, Shin, JH, Cymes, G, Kasperek, E, Cao, FL & Nicholson, BJ 2002, 'Identification of amino acid residues lining the pore of a gap junction channel', Journal of Cell Biology, vol. 159, no. 2, pp. 349-359. https://doi.org/10.1083/jcb.200207060
Skerrett IM, Aronowitz J, Shin JH, Cymes G, Kasperek E, Cao FL et al. Identification of amino acid residues lining the pore of a gap junction channel. Journal of Cell Biology. 2002 Oct 28;159(2):349-359. https://doi.org/10.1083/jcb.200207060
Skerrett, I. M. ; Aronowitz, J. ; Shin, J. H. ; Cymes, G. ; Kasperek, E. ; Cao, F. L. ; Nicholson, Bruce J. / Identification of amino acid residues lining the pore of a gap junction channel. In: Journal of Cell Biology. 2002 ; Vol. 159, No. 2. pp. 349-359.
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