Journal: Cells
Article Title: Annexin A2 Egress during Calcium-Regulated Exocytosis in Neuroendocrine Cells
doi: 10.3390/cells9092059
Figure Lengend Snippet: Tissue plasminogen activator (t-PA) is present on the outer leaflet of the plasma membrane of stimulated chromaffin cells. ( a ) Dual labeling of cell surface t-PA and exocytotic sites. Cells were stimulated with nicotine 20 µM in the presence of anti-t-PA and anti-DBH antibodies. Cells were then fixed and incubated with secondary antibodies coupled to Alexa Fluor ® 488 and Alexa Fluor ® 551, respectively. Confocal images were recorded in the same optical section and with the same parameters of lasers and photomultipliers. Scale bar: 10 µM. ( b ) The t-PA labeling on the surface of chromaffin cells in the resting condition (R), stimulated with 20 µM nicotine without (S) or after EGTA wash (S + EGTA). Anti-t-PA antibodies were revealed with Alexa Fluor ® 488-conjugated anti-rabbit antibodies and F-actin with TRITC-phalloidin to visualize the cell shape. Confocal images were recorded in the same optical section by a dual exposure procedure. Scale bar: 10 µM. ( c ) Semi-quantitative analysis of t-PA labeling on the cell surface of chromaffin cells in the resting condition (R), stimulated with 20 µM nicotine (S) without (Control) or after EGTA wash (S + EGTA). The t-PA labeling is expressed in arbitrary units. Statistical significance for medians was determined using a Mann-Whitney test. Dotted lines indicate the mean and asterisks statistical significance (*** = p < 0.001, ** = p < 0.01). Three experiments were done on independent cell cultures and pooled ( n = 36 and 65 control cells, 40 and 75 EGTA-treated cells for resting and stimulated conditions, respectively). ( d ) Lysate, secreted material and EGTA eluate from chromaffin cells in the resting condition (R) or stimulated with nicotine 20 µM (S) were analyzed by western blot and revealed with anti-t-PA and anti-AnxA2 antibodies. Data correspond to a typical experiment representative of three independent experiments.
Article Snippet: Rabbit polyclonal anti-mouse tissue plasminogen activator (t-PA) antibodies were from Molecular Innovations (Novi, MI, USA).
Techniques: Labeling, Incubation, MANN-WHITNEY, Western Blot