endogenous hsc70  (StressMarq)

Journal: Frontiers in Molecular Neuroscience

Article Title: Chaperone-Mediated Regulation of Choline Acetyltransferase Protein Stability and Activity by HSC/HSP70, HSP90, and p97/VCP

doi: 10.3389/fnmol.2017.00415

Figure Lengend Snippet: Co-immunoprecipitation (co-IP) of ChAT with heat shock proteins HSC70, HSP70, and HSP90 is altered by mutation of N-terminal proline-rich motif in ChAT. (A) Immunoblots showing co-IP of ChAT with endogenous HSC70, HSP70 and HSP90 from HEK293 cells expressing either wild-type or P17A/P19A-ChAT. Control cells were transfected with empty vector. Using HEK293 cells, co-IP of P17A/P19A-ChAT with HSP70 (B) , HSP90 (C) and HSC70 (D) , respectively, is greater than that of wild-type ChAT ( *** p ≤ 0.001, Student's t -test, mean ± SEM, n = 4). (E) Co-IP of ChAT with endogenous HSC70 and HSP90 from mouse cholinergic SN56 cells expressing either wild-type or P17A/P19A-ChAT or CMS-related mutant proteins V18M- or A513T-ChAT. Control cells were transfected with empty vector. (F) Using SN56 cells, Co-IP of P17A/P19A-ChAT ( *** p ≤ 0.001) and V18M-ChAT ( * p ≤ 0.05), but not A531T-ChAT, with HSC70 is greater than that of wild-type ChAT (mean ± SEM, n = 5). (G) While there was a trend toward increased HSP90 interaction with P17A/P19A-ChAT ( p = 0.09), no significant differences were observed for HSP90 interaction with mutant ChAT compared to wild-type ChAT in SN56 cells (mean ± SEM, n = 5). Statistical analysis for (F) and (G) was performed by one-way ANOVA with Dunnett's post-hoc test. (H) Detection of in situ interactions of wild-type ChAT with endogenous HSC70 and HSP90 by proximity ligation assay (PLA) in SN56 cells. Formalin-fixed cells were first co-labeled with goat anti-ChAT together with either mouse anti-HSC70 or mouse anti-HSP90 primary antibodies, then incubated with oligonucleotide-linked secondary antibodies. Following DNA ligation and DNA amplification using the Duolink in Situ Orange Kit (Sigma), in situ ChAT-HSP interactions were imaged by confocal microscopy. Positive in situ ChAT-HSP interactions where visualized as fluorescent red dots while nuclei were stained with DAPI (blue). Control cells were either transfected with empty vector or had primary antibodies omitted from the assay (No 1° antibodies). Images are representative of 3 independent experiments; scale bars are 10 μm.

Article Snippet: Cells were washed with HBSS, formalin-fixed (4% paraformaldehyde in HBSS) for 15 min, permeabilized with 0.1% Triton X-100, blocked for 1 h in HBSS supplemented with 3% donkey serum, then finally incubated for 1 h with primary antibodies targeting ChAT (1:100; Chemicon, goat primary) together with either endogenous HSC70 (1:100; StressMarq, mouse primary), HSP90 (1:200; StressMarq, mouse primary) or CHIP (1:200; Santa Cruz, rabbit primary); all steps were performed at room temperature.

Techniques: Immunoprecipitation, Co-Immunoprecipitation Assay, Mutagenesis, Western Blot, Expressing, Transfection, Plasmid Preparation, In Situ, Proximity Ligation Assay, Labeling, Incubation, DNA Ligation, Amplification, Confocal Microscopy, Staining

Journal: Frontiers in Molecular Neuroscience

Article Title: Chaperone-Mediated Regulation of Choline Acetyltransferase Protein Stability and Activity by HSC/HSP70, HSP90, and p97/VCP

doi: 10.3389/fnmol.2017.00415

Figure Lengend Snippet: ChAT interacts with the HSP-associated E3 ubiquitin ligase C-terminus of HSC70-interaction protein (CHIP). (A) Immunoblots showing co-IP of ChAT with FLAG-CHIP from SN56 cells co-expressing either wild-type or mutant ChAT protein with FLAG-tagged CHIP. Control cells were transfected with either empty vector or to express either wild-type ChAT or FLAG-CHIP alone. (B) Co-IP of ChAT with FLAG-CHIP is enhanced for P17A/P19A- ( *** p ≤ 0.001), V18M- ( *** p ≤ 0.001), and A513T-ChAT ( * p ≤ 0.05) as compared to wild-type ChAT (one-way ANOVA with Dunnett's post-hoc test, mean ± SEM, n = 5). (C) Co-IP of wild-type and mutant ChAT with endogenous CHIP following anti-ChAT co-IP from ChAT-expressing SN56 cells ( n = 3). (D) Detection of in situ ChAT interactions with endogenous CHIP by proximity ligation assay (PLA) in SN56 cells expressing wild-type ChAT. Formalin-fixed cells were first co-labeled with goat anti-ChAT together with rabbit anti-CHIP primary antibodies, then incubated with oligonucleotide-linked secondary antibodies. Following DNA ligation and DNA amplification using the Duolink In Situ Orange Kit (Sigma), in situ ChAT-CHIP interactions were imaged by confocal microscopy. Positive in situ ChAT-CHIP interactions were visualized as fluorescent red dots while nuclei were stained with DAPI (blue). Control cells were either transfected with empty vector or primary antibodies omitted from the assay (No 1° antibodies). Images are representative of 4 independent experiments; scale bars are 10 μm. (E) siRNA-mediated knock-down of CHIP has no effect on the steady-state protein levels of either wild-type or mutant ChAT. ChAT-expressing SN56 cells were co-transfected with 25 nM of either anti-CHIP siRNA or scramble-control siRNA for 72 h. Control cells were mock-transfected ( n = 4).

Article Snippet: Cells were washed with HBSS, formalin-fixed (4% paraformaldehyde in HBSS) for 15 min, permeabilized with 0.1% Triton X-100, blocked for 1 h in HBSS supplemented with 3% donkey serum, then finally incubated for 1 h with primary antibodies targeting ChAT (1:100; Chemicon, goat primary) together with either endogenous HSC70 (1:100; StressMarq, mouse primary), HSP90 (1:200; StressMarq, mouse primary) or CHIP (1:200; Santa Cruz, rabbit primary); all steps were performed at room temperature.

Techniques: Western Blot, Co-Immunoprecipitation Assay, Expressing, Mutagenesis, Transfection, Plasmid Preparation, In Situ, Proximity Ligation Assay, Labeling, Incubation, DNA Ligation, Amplification, Confocal Microscopy, Staining