FIGURE 2:

Munc13-4 localizes to WPBs and the plasma membrane independently of Rab27a. (a) Confocal section of fixed HUVECs expressing YFP–Munc13-4 for 48 h and labeled with anti-VWF and Alexa Fluor 568–conjugated secondary antibodies. (b) TIRF section of live HUVECs expressing YFP–Munc13-4 and the PI(4,5)P₂-binding domain PLCδ4-PH-mKate as membrane marker. (c) Confocal section of fixed HUVECs expressing GFP–Munc13-4(Δ280-285), a mutant incapable of binding Rab27a, and labeled with anti-VWF and Alexa Fluor 568–conjugated secondary antibodies. (d) Confocal section of fixed HUVECs expressing YFP–Munc13-4 and transfected with siRNA against Rab27a (siRab27a) for 48 h. Cells were labeled with anti-VWF and Alexa Fluor 568–conjugated secondary antibodies. Arrowheads mark examples of colocalizations of Munc13-4 and VWF on WPBs. Scale bars, 10 µm.