Figure 4

Subcellular localization of mPARM-1 and hPARM-1 (full-length and mutant proteins). (a) NIH/3T3 cells, transiently transfected with GFP-tagged mParm-1 or hParm-1 constructs were visualized using confocal microscopy. (b) For the Golgi co-localization, transfected NIH/3T3 cells were fixed and stained with Bodipy ceramide marker. For late and early endosomes co-localization, fixed cells were labeled with (c) anti-Rab5 (early endosomes (1:100, Cell signaling)) and (d) anti-Rab7 (late endosomes (1:100, Cell signaling)) antibodies, respectively. Jurkat T cells, transiently transfected with hParm-1-GFP proteins were visualized (e) without fixation or (f) following fixation and staining with CellMask plasma membrane labeling. NIH/3T3 cells were transiently transfected with (g) ∆EC-GFP, (h) ∆SP-GFP, (i) EC-GFP, (j) ∆TM-GFP and (k) ∆CT-GFP constructs of hPARM-1 and visualized using confocal microscopy. (l) hPARM-1-GFP co-localizes with microtubules. NIH/3T3 cells transfected with hParm-1-GFP construct were fixed and stained with anti-α-tubulin (1/2000, Sigma) antibody. Arrows indicate co-localized hPARM-1-GFP vesicles and microtubules. NIH/3T3 cells transiently expressing (m) hPARM-1-GFP or (n) ∆CT-GFP were fixed, immunostained for caveolin-1 (1:100, Novus Biologicals), and examined by confocal fluorescence microscopy. For hPARM-1-GFP-caveolin-1 co-localization, cells that clearly demonstrated cell membrane PARM-1 localization were chosen. All co-localizations were observed following merging images of GFP-tagged proteins with those of Golgi, endosomes, plasma membrane, α-tubulin or caveolin-1 labeling. Cells were imaged with a laser-scanning confocal microscope (Bio-Rad MRC-1024 ES) mounted on a Nikon TE-300 using a Plan Apochromat 60x (NA 1.40) oil objective (Nikon), digitally acquired using Laser Sharp software Version 3.2 (Bio-Rad). For live cell imaging, signals were collected at a rate of 2 seconds. Images were analyzed using NIH ImageJ Version 1.42l software. Data are representative of 3 independent experiments.