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 language | English (US) |
|---|---|
| Pages (from-to) | 157-166 |
| Number of pages | 10 |
| Journal | Channels |
| Volume | 8 |
| Issue number | 2 |
| DOIs | |
| State | Published - 2014 |
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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 journal › Article
}
TY - JOUR
T1 - Structural order in Pannexin 1 cytoplasmic domains
AU - Spagnol, Gaelle
AU - Sorgen, Paul L.
AU - Spray, David C.
PY - 2014
Y1 - 2014
N2 - 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.
AB - 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.
KW - Caspase-3
KW - Circular dichroism
KW - Cytoplasmic domains
KW - NMR
KW - Panx1
UR - http://www.scopus.com/inward/record.url?scp=84901453448&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84901453448&partnerID=8YFLogxK
U2 - 10.4161/chan.28854
DO - 10.4161/chan.28854
M3 - Article
C2 - 24751934
AN - SCOPUS:84901453448
VL - 8
SP - 157
EP - 166
JO - Channels
JF - Channels
SN - 1933-6950
IS - 2
ER -