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Sci Rep
2016 Dec 08;6:38788. doi: 10.1038/srep38788.
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Intermolecular Interactions in the TMEM16A Dimer Controlling Channel Activity.
Scudieri P
,
Musante I
,
Gianotti A
,
Moran O
,
Galietta LJ
.
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TMEM16A and TMEM16B are plasma membrane proteins with Ca2+-dependent Cl- channel function. By replacing the carboxy-terminus of TMEM16A with the equivalent region of TMEM16B, we obtained channels with potentiation of channel activity. Progressive shortening of the chimeric region restricted the "activating domain" to a short sequence close to the last transmembrane domain and led to TMEM16A channels with high activity at very low intracellular Ca2+ concentrations. To elucidate the molecular mechanism underlying this effect, we carried out experiments based on double chimeras, Forster resonance energy transfer, and intermolecular cross-linking. We also modeled TMEM16A structure using the Nectria haematococca TMEM16 protein as template. Our results indicate that the enhanced activity in chimeric channels is due to altered interaction between the carboxy-terminus and the first intracellular loop in the TMEM16A homo-dimer. Mimicking this perturbation with a small molecule could be the basis for a pharmacological stimulation of TMEM16A-dependent Cl- transport.
Figure 2. Altered membrane currents in TMEM16A proteins with chimeric C-termini.(A) Representative membrane currents in HEK-293 cells expressing wild type TMEM16A or C-TERM/C-TERM4 mutants. Each panel reports superimposed currents elicited at different membrane voltages (−100 to +100 mV range) and at the indicated intracellular free Ca2+ concentrations. (B) Current-voltage relationships summarizing the results of experiments as those shown in (A). Each point is the mean ± SEM of 9–12 experiments.
Figure 4. Channel activity in double chimeric TMEM16A proteins.(A) Results from HS-YFP assay carried out on HEK-293 cells expressing the indicated constructs. Gray bars: anion transport in the absence of intracellular Ca2+ elevation. White bars: anion transport after stimulation with ionomycin (1 μM). #p < 0.05 vs. C-TERM1 (n = 6–9 experiments). (B) Representative traces from HS-YFP experiments. (C) Representative whole-cell membrane currents and current-voltage relationships from 6–9 experiments with the indicated TMEM16A constructs. Intracellular free Ca2+ concentration was 7 or 245 nM.
Brunner,
X-ray structure of a calcium-activated TMEM16 lipid scramblase.
2014, Pubmed,
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Brunner,
X-ray structure of a calcium-activated TMEM16 lipid scramblase.
2014,
Pubmed
,
Echinobase
Brunner,
Structural basis for phospholipid scrambling in the TMEM16 family.
2016,
Pubmed
Caputo,
TMEM16A, a membrane protein associated with calcium-dependent chloride channel activity.
2008,
Pubmed
Fallah,
TMEM16A(a)/anoctamin-1 shares a homodimeric architecture with CLC chloride channels.
2011,
Pubmed
Ferrera,
Regulation of TMEM16A chloride channel properties by alternative splicing.
2009,
Pubmed
Huang,
Calcium-activated chloride channels (CaCCs) regulate action potential and synaptic response in hippocampal neurons.
2012,
Pubmed
Humphrey,
VMD: visual molecular dynamics.
1996,
Pubmed
Krieger,
Increasing the precision of comparative models with YASARA NOVA--a self-parameterizing force field.
2002,
Pubmed
Krieger,
YASARA View - molecular graphics for all devices - from smartphones to workstations.
2014,
Pubmed
Pedemonte,
Structure and function of TMEM16 proteins (anoctamins).
2014,
Pubmed
Phillips,
Scalable molecular dynamics with NAMD.
2005,
Pubmed
Pifferi,
TMEM16B induces chloride currents activated by calcium in mammalian cells.
2009,
Pubmed
Ryckaert,
Shear-rate dependence of the viscosity of simple fluids by nonequilibrium molecular dynamics.
1988,
Pubmed
Schroeder,
Expression cloning of TMEM16A as a calcium-activated chloride channel subunit.
2008,
Pubmed
Scudieri,
TMEM16A-TMEM16B chimaeras to investigate the structure-function relationship of calcium-activated chloride channels.
2013,
Pubmed
Scudieri,
Association of TMEM16A chloride channel overexpression with airway goblet cell metaplasia.
2012,
Pubmed
Sheridan,
Characterization of the oligomeric structure of the Ca(2+)-activated Cl- channel Ano1/TMEM16A.
2011,
Pubmed
Sondo,
The TMEM16A chloride channel as an alternative therapeutic target in cystic fibrosis.
2014,
Pubmed
Sondo,
Non-canonical translation start sites in the TMEM16A chloride channel.
2014,
Pubmed
Stephan,
ANO2 is the cilial calcium-activated chloride channel that may mediate olfactory amplification.
2009,
Pubmed
Stöhr,
TMEM16B, a novel protein with calcium-dependent chloride channel activity, associates with a presynaptic protein complex in photoreceptor terminals.
2009,
Pubmed
Suzuki,
Calcium-dependent phospholipid scramblase activity of TMEM16 protein family members.
2013,
Pubmed
Suzuki,
Calcium-dependent phospholipid scrambling by TMEM16F.
2010,
Pubmed
Tien,
A comprehensive search for calcium binding sites critical for TMEM16A calcium-activated chloride channel activity.
2014,
Pubmed
Xiao,
Voltage- and calcium-dependent gating of TMEM16A/Ano1 chloride channels are physically coupled by the first intracellular loop.
2011,
Pubmed
Yang,
TMEM16A confers receptor-activated calcium-dependent chloride conductance.
2008,
Pubmed
Yu,
Explaining calcium-dependent gating of anoctamin-1 chloride channels requires a revised topology.
2012,
Pubmed
