These were most likely postsynaptic receptor clusters, since they were juxtaposed to, but did not overlap with, presynaptic synaptobrevin (SNB-1GFP; Figure 2C; Supplementary Figure 6C)

These were most likely postsynaptic receptor clusters, since they were juxtaposed to, but did not overlap with, presynaptic synaptobrevin (SNB-1GFP; Figure 2C; Supplementary Figure 6C). a viable approach to identify novel proteins regulating neurotransmitter receptor activity or expression in model systems like muscle, also the FGF receptor can induce nAChR clustering (Peng is the levamisole-sensitive nAChR (levamisole receptor), which is expressed in muscles and (motor-) neurons (Fleming interaction in of those subunits in a single nAChR has not been shown, and the exact subunit composition of the levamisole receptor is not clear. By electrophysiology, UNC-29 and UNC-38 are required for levamisole receptor function at the neuromuscular junction (NMJ), but not for function of another, pharmacologically different nAChR (Richmond and Jorgensen, 1999). Three additional genes have recently been shown to encode potential nAChR accessory proteins: (1) RIC-3 enhances the expression of multiple nAChRs in the cell periphery and on the plasma Rabbit Polyclonal to Cytochrome P450 2U1 membrane of heterologous cells (Halevi situation. Here we report identification and characterization of proteins associated with the levamisole receptor. We used, for the first time in loss-of-function mutants (Figure 1C). To avoid purification of proteins that associate only with UNC-29 monomers, we varied the TAP purification, using a split’ TAP tag. We fused the Protein A/TEV tag to UNC-29 and the CBP tag to LEV-1; thus, only assembled complexes containing both subunits would be purified. Alternatively, we generated a strain that coexpressed UNC-29TAP with hexa-histidine-tagged versions of LEV-1, UNC-38, and UNC-63, allowing Ni2+ chromatography as a third purification step. In total, four purifications were performed: two with the simple TAP tag on UNC-29, one with the third Ni2+ chromatography, and one with the split TAP tag. As a control, we also performed Iproniazid a mock purification from a wild-type (WT) extract containing no tagged protein (Figure 1D; Supplementary Figure 7 (for stronger contrast)). Open in a separate Iproniazid window Figure 1 TAP of the levamisole receptor. (A) Immunodetection of the ProtA portion of UNC-29TAP (lane 1, *) in detergent extracts of strain AQ748 and N2 (WT, lane 2). (B) UNC-29TAP and UNC-29TEV-ProtA were precipitated with IgG agarose from detergent extracts of strains AQ748 or AQ839, respectively, and detected by Western analysis directed against the ProtA portion of the respective tags. (C) Paralysis by nicotine (31 mM). WT (N2) or mutants (genotype as indicated) and the same mutants rescued with the respective integrated arrays (strains AQ748 and AQ839) were placed on nicotine plates and observed at the indicated times to determine the fraction of paralyzed animals (3C5 experiments, proteome database (Tabb (a Tc1 transposon insertion, and mutations conferred nicotine resistance, did not. Moreover, only animals were levamisole resistant. Thus, not all of the nAChR subunits copurified equally contribute to levamisole receptor function. Open in a separate window Figure 2 Analysis of novel nAChR subunits copurified with the levamisole receptor. (A, B) Paralysis of mutants lacking additional nAChR -subunits that copurified with the levamisole receptor, mutant animals were also analyzed (3C6 experiments, with fluorescent (Cy3-labeled, red) antibodies directed against the extracellular cMYC epitope. Antibodies were injected into the pseudocoelom of animals expressing UNC-383xMYC and the Iproniazid presynaptic vesicle marker synaptobrevin SNB-1GFP (green), driven by the promoter (strain AQ898). (D) Complete synaptic colocalization of UNC-29GFP and UNC-383xMYC, labeled with anti-MYC-Cy3 antibodies injected into the pseudocoelom (strain AQ658). (E, F) Partial synaptic colocalization of either ACR-123xHA (E; strain AQ1013) or ACR-83xHA (F; strain AQ1011) with UNC-383xMYC, each labeled with injected fluorescent antibodies (anti-HA-Alexa488, green; anti-MYC-Cy3, red). Colocalization in the same nervecord cluster is indicated by arrowheads. In (CCE), the ventral nervecord of adult animals in the midbody region, within 1/4 body length anterior or posterior of the vulva is shown; anterior is left; scale bars=20 m. The finding that five nAChR -subunits were copurified with the two non–subunits LEV-1 and UNC-29 could indicate that multiple distinct classes of levamisole receptors with differing -subunit composition may exist. To address this possibility, we studied the expression patterns.