Figure 5
From: Axonal BACE1 dynamics and targeting in hippocampal neurons: a role for Rab11 GTPase
Localization and dynamic transport of BACE1 in recycling endosomes. (A) Colocalization of BACE1 with endogenous syntaxin 13 in dendrites and axons of cultured hippocampal neurons (DIV12). Insets show higher magnification of the boxed area. Images of the dendrites were acquired by confocal microscopy and those of the axon were generated by deconvolution of widefield z-stacks. Dendrites and axons were identified by the presence and absence of MAP2 staining, respectively. (B) Analysis of BACE1 colocalization with Rab11b in dendrites and axons. DIV12 neurons co-transfected with BACE1-YFP and mCherry-Rab11b were immunostained for MAP2. Insets show higher magnification of the area marked by a yellow arrowhead on a dendrite or the boxed area in an axon. Arrowheads indicate vesicles positive for BACE1 and Rab11b along the axon. Manders’ coefficient of colocalization (M Coeff) is indicated (n = 7 neurons). (C) Visualization of BACE1-YFP and mCherry-Rab11b dynamic co-transport by dual-color live cell imaging. Time-lapse images were acquired using the Dual-View two-channel simultaneous-imaging system at the rate of 1 frame/sec for 3 min (Additional file 4). Kymograph analysis reveals bidirectional transport of BACE1 in Rab11b-positive endosomes (yellow tracks in the overlay panels) in both dendrites and axons.