Journal: The Journal of Biological Chemistry
Article Title: Trans -2-enoyl-CoA reductase limits Ca 2+ accumulation in the endoplasmic reticulum by inhibiting the Ca 2+ pump SERCA2b
doi: 10.1016/j.jbc.2021.100310
Figure Lengend Snippet: The C-terminal region of TER is essential for the binding to SERCA2b. A , left , predicted topology of TER. The topology was based on previous literatures ( , ). Right , domain structure of full-length TER and the deletion mutants used in this study. B , coimmunoprecipitation analysis of SERCA2b and TER deletion mutants. 3xHA-SERCA2b and FLAG-empty vector, FLAG–TER FL, FLAG–TER-N-term, FLAG–TER (ΔC or ΔN), or FLAG–KAR were transfected into HEK293 cells. KAR, another essential component of the FA elongation cycle, was included as a negative control. The Triton X-100 extracts of the transfected cells were immunoprecipitated with anti-FLAG mAb and then subjected to Western blotting with anti-HA mAb or anti-FLAG pAb. The asterisks (∗) indicate nonspecific bands in the IP. Data are representative of three independent experiments. C , binding of the C-terminal region of TER to SERCA2b. 3xHA-SERCA2b was transfected into HEK293 cells, and the Triton X-100 extracts of the transfected cells were incubated with 2.8 nmol of GST, GST-TER-N-term, or GST-TER-C-term immobilized on glutathione Sepharose. The bound proteins were eluted with the SDS sample buffer and subjected to SDS-PAGE followed by Western blotting with anti-HA mAb or CBB staining. Data are representative of two independent experiments. D , inhibition of the binding between the C-terminal region of TER and SERCA2b by Tg. HEK293 cells expressing 3xHA-SERCA2b were treated with or without 1 μM Tg for 90 min, and the Triton X-100 extracts of these cells were subjected to the pull-down assay as in panel C with 1.9 nmol of GST or GST-TER-C-term immobilized on glutathione Sepharose. This experiment was performed once. The double asterisks (∗∗) in panels C and D indicate the degradation products of GST-TER-C-term. CBB, Coomassie Brilliant Blue; FA, fatty acid; FLAG–TER, recombinant TER with an N-terminal FLAG-tag; GST, glutathione-S-transferase; KAR, 3-ketoacyl-CoA reductase; SERCA2b, sarco(endo)plasmic reticulum Ca 2+ -ATPase 2b; TER, trans -2-enoyl-CoA reductase; Tg, thapsigargin; TM, transmembrane region; pAb, polyclonal antibody.
Article Snippet: The following reagents were purchased from the indicated manufacturers: mouse anti-SERCA2b mAb (clone IID8 , Cat. No. sc-53010, for Western blotting) from Santa Cruz Biotechnology; mouse anti-SERCA2b mAb (clone 2A7-A1 , Cat. No. NB300-581, for immunostaining) from Novus; rabbit anti-TER polyclonal antibody (pAb) (Cat. No. A305-515A) from Bethyl Laboratories; horseradish peroxidase–conjugated Strep-Tactin from IBA Lifesciences; rat anti-HA mAb (clone 3F10, Cat. No. 11867431001) from Roche; mouse anti-HA mAb (clone 16B12, Cat. No. 901513) from BioLegend; rabbit anti-FLAG pAb (Cat. No. F7425), mouse anti-FLAG mAb (clone M2, Cat. No. F1804), mouse anti-β-actin mAb (clone AC-74, Cat. No. A2228) from Sigma; rabbit anti-Calnexin mAb (clone C5C9, Cat. No. 2679S) and normal rabbit IgG (Cat. No. 2729S) from Cell Signaling Technology.
Techniques: Binding Assay, Plasmid Preparation, Transfection, Negative Control, Immunoprecipitation, Western Blot, Incubation, SDS Page, Staining, Inhibition, Expressing, Pull Down Assay, Recombinant, FLAG-tag