Improved gating of a chimeric alpha7-5HT3A receptor upon mutations at the M2-M3 extracellular loop.
Acetylcholine-evoked currents of the receptor chimera alpha7-5HT3A V201 expressed in Xenopus oocytes are strikingly small when compared to the amount of alpha-bungarotoxin binding sites detected at the oocyte membrane. Since the chimeric receptor is made of the extracellular N-terminal region of the rat alpha7 nicotinic acetylcholine receptor and the C-terminal region of the mouse 5-HT3A receptor, which includes the ion channel, we hypothesized that communication between these two regions was not optimal. Here, we show that mutating to aspartate several adjacent positions in the M2-M3 extracellular linker increases current amplitudes to different extents, thus confirming the important role of this region on receptor gating.
Castillo
Mar
M
Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-C.S.I.C., 03550-Sant Joan d'Alacant, Alicante, Spain.
Mulet
José
J
Bernal
José Antonio
JA
Criado
Manuel
M
Sala
Francisco
F
Sala
Salvador
S
D019943:Amino Acid Substitution; D000818:Animals; D001224:Aspartic Acid / Q000235:genetics / Q000378:metabolism; D002038:Bungarotoxins / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics; D009865:Oocytes / Q000378:metabolism; D017354:Point Mutation; D017433:Protein Structure, Secondary / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D051381:Rats; D011978:Receptors, Nicotinic / Q000235:genetics / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014981:Xenopus; D064569:alpha7 Nicotinic Acetylcholine Receptor
D002038:Bungarotoxins; C579166:Chrna7 protein, mouse; C579165:Chrna7 protein, rat; D011978:Receptors, Nicotinic; D011985:Receptors, Serotonin; D011993:Recombinant Fusion Proteins; D064569:alpha7 Nicotinic Acetylcholine Receptor; C078730:serotonin 5 receptor; D001224:Aspartic Acid