All lanes : Anti-ERK5 antibody [EP791Y] (ab40809) at 1/1000 dilution

Lane 1 : Wild-type HeLa cell lysate
Lane 2 : MAPK7 knockout HeLa cell lysate

Lysates/proteins at 20 µg per lane.

Performed under reducing conditions.

Predicted band size: 89 kDa
Observed band size: 115 kDa why is the actual band size different from the predicted?

Lanes 1- 2: Merged signal (red and green). Green - ab40809 observed at 115 kDa. Red - Anti-GAPDH antibody [6C5] - Loading Control (ab8245) observed at 37 kDa.

 ab40809 was shown to react with ERK5 in wild-type HeLa cells in western blot. Loss of signal was observed when knockout cell line ab265508 (knockout cell lysate ab258042) was used. Wild-type HeLa and MAPK7 knockout HeLa cell lysates were subjected to SDS-PAGE. Membrane was blocked for 1 hour at room temperature in 0.1% TBST with 3% non-fat dried milk. ab40809 and Anti-GAPDH antibody [6C5] - Loading Control (ab8245) overnight at 4°C at a 1 in 1000 dilution and a 1 in 20000 dilution respectively. Blots were developed with Goat anti-Rabbit IgG H&L (IRDye^®800CW) preadsorbed (ab216773) and Goat anti-Mouse IgG H&L (IRDye^®680RD) preadsorbed (ab216776) secondary antibodies at 1 in 20000 dilution for 1 hour at room temperature before imaging.

Immunocytochemistry/ Immunofluorescence analysis of HeLa (Human cervix adenocarcinoma epithelial cell) cells labeling ERK5 with Purified ab40809 at 1:100 (4.8 µg/ml). Cells were fixed in 4% Paraformaldehyde and permeabilized with 0.1% tritonX-100. Cells were counterstained with Ab195889 Anti-alpha Tubulin antibody [DM1A] - Microtubule Marker (Alexa Fluor^® 594) 1:200 (2.5 µg/ml). Goat anti rabbit IgG (Alexa Fluor^® 488, ab150077) was used as the secondary antibody at 1:1000 (2 μg/ml) dilution. DAPI nuclear counterstain. PBS instead of the primary antibody was used as the secondary antibody only control.

Flow Cytometry analysis of HeLa (Human cervix adenocarcinoma epithelial cell) cells labeling ERK5 with purified ab40809 at 1:50 dilution (10 ug/ml) (red). Cells were fixed with 80% methanol. A Goat anti rabbit IgG (Alexa Fluor^® 488) secondary antibody was used at 1:2000 dilution. Isotype control - Rabbit monoclonal IgG (Black). Unlabeled control - Cell without incubation with primary antibody and secondary antibody (Blue).

All lanes : Anti-ERK5 antibody [EP791Y] (ab40809) at 1/2000 dilution (Purified)

Lane 1 : HeLa (Human cervix adenocarcinoma epithelial cell) whole cell lysates with 5% NFDM/TBST
Lane 2 : NIH/3T3 (Mouse embryonic fibroblast) whole cell lysates with 5% NFDM/TBST
Lane 3 : PC-12 (Rat adrenal gland pheochromocytoma) whole cell lysates with 5% NFDM/TBST

Lysates/proteins at 15 µg per lane.

Secondary
All lanes : Goat Anti-Rabbit IgG H&L (HRP) (ab97051) at 1/20000 dilution (Goat Anti-Rabbit IgG, (H+L), Peroxidase conjugated)

Predicted band size: 89 kDa
Observed band size: 115 kDa why is the actual band size different from the predicted?

Lane 1: Wild-type HAP1 whole cell lysate (20 µg)
Lane 2: MAPK7 (ERK5) knockout HAP1 whole cell lysate (20 µg)
Lane 3: HeLa whole cell lysate (20 µg)

Lanes 1 - 3: Merged signal (red and green). Green - ab40809 observed at 88 kDa. Red - loading control, ab9484, observed at 37 kDa.

Unpurified ab40809 was shown to specifically react with ERK5 in wild-type HAP1 cells as signal was lost in MAPK7 (ERK5) knockout cells. Wild-type and MAPK7 (ERK5) knockout samples were subjected to SDS-PAGE. Unpurified ab40809 and ab9484 (Mouse anti-GAPDH loading control) were incubated overnight at 4°C at 1/1000 dilution and 1/20000 dilution respectively. Blots were developed with Goat anti-Rabbit IgG H&L (IRDye^® 800CW) preabsorbed ab216773 and Goat anti-Mouse IgG H&L (IRDye^® 680RD) preabsorbed ab216776 secondary antibodies at 1/20000 dilution for 1 hour at room temperature before imaging.

Anti-ERK5 antibody [EP791Y] (ab40809) at 1/5000 dilution (unpurified) + Hela cell lysate at 10 µg

Predicted band size: 89 kDa
Observed band size: 115 kDa why is the actual band size different from the predicted?



The predicted weight of 89 kDa is for the precursor version of human ERK5 protein. However, ab40809 detects endogenous levels of total Erk5 protein which appears around 115 kDa in SDS PAGE

Overlay histogram showing A549 cells stained with unpurified ab40809 (red line). The cells were fixed with 80% methanol (5 min) and then permeabilized with 0.1% PBS-Tween for 20 min. The cells were then incubated in 1x PBS / 10% normal goat serum / 0.3M glycine to block non-specific protein-protein interactions followed by the antibody (ab40809, 1/100 dilution) for 30 min at 22°C. The secondary antibody used was Alexa Fluor® 488 goat anti-rabbit IgG (H&L) (ab150077) at 1/2000 dilution for 30 min at 22°C. Isotype control antibody (black line) was rabbit IgG (monoclonal) (1μg/1x10⁶ cells) used under the same conditions. Unlabelled sample (blue line) was also used as a control. Acquisition of >5,000 events were collected using a 20mW Argon ion laser (488nm) and 525/30 bandpass filter.

ab40809 (purified) at 1:30 dilution (2ug) immunoprecipitating ERK5 in HeLa whole cell lysate.
Lane 1 (input): HeLa (Human cervix adenocarcinoma epithelial cell) whole cell lysate 10ug
Lane 2 (+): ab40809 & HeLa whole cell lysate
Lane 3 (-): Rabbit monoclonal IgG (ab172730) instead of ab40809 in HeLa whole cell lysate
For western blotting, VeriBlot for IP Detection Reagent (HRP) (ab131366) was used for detection at 1:1000 dilution.
Blocking and diluting buffer: 5% NFDM/TBST.