Structural order in Pannexin 1 cytoplasmic domains

Gaelle Spagnol, Paul L. Sorgen, David C. Spray

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Pannexin 1 forms ion and metabolite permeable hexameric channels with abundant expression in the central nervous system and elsewhere. Although pannexin 1 does not form intercellular channels, a common channel topology and oligomerization state, as well as involvement of the intracellular carboxyl terminal (CT) domain in channel gating, is shared with connexins. In this study, we characterized the secondary structure of the mouse pannexin 1 cytoplasmic domains to complement structural studies of the transmembrane segments and compare with similar domains from connexins. A combination of structural prediction tools and circular dichroism revealed that, unlike connexins (predominately intrinsically disordered), cytosolic regions of pannexin 1 contain approximately 50% secondary structure, a majority being α-helical. Moreover, prediction of transmembrane domains uncovered a potential membrane interacting region (I360-G370) located upstream of the caspase cleavage site (D375-D378) within the pannexin 1 CT domain. The α-helical content of a peptide containing these domains (G357-S384) increased in the presence of detergent micelles providing evidence of membrane association. We also purified a pannexin 1 CT construct containing the caspase cleavage site (M374-C426), assigned the resonances by NMR, and confirmed cleavage by Caspase-3 in vitro. On the basis of these structural studies of the cytoplasmic domains of pannexin 1, we propose a mechanism for the opening of pannexin 1 channels upon apoptosis, involving structural changes within the CT domain.

Original languageEnglish (US)
Pages (from-to)157-166
Number of pages10
JournalChannels
Volume8
Issue number2
DOIs
StatePublished - 2014

Fingerprint

Connexins
Caspases
Membranes
Oligomerization
Neurology
Micelles
Metabolites
Circular Dichroism
Caspase 3
Detergents
Membrane Potentials
Central Nervous System
Nuclear magnetic resonance
Topology
Association reactions
Ions
Apoptosis
Peptides

Keywords

  • Caspase-3
  • Circular dichroism
  • Cytoplasmic domains
  • NMR
  • Panx1

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Medicine(all)

Cite this

Structural order in Pannexin 1 cytoplasmic domains. / Spagnol, Gaelle; Sorgen, Paul L.; Spray, David C.

In: Channels, Vol. 8, No. 2, 2014, p. 157-166.

Research output: Contribution to journalArticle

Spagnol, Gaelle ; Sorgen, Paul L. ; Spray, David C. / Structural order in Pannexin 1 cytoplasmic domains. In: Channels. 2014 ; Vol. 8, No. 2. pp. 157-166.
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