MyoVb is Concentrated in Dendritic Spines and Traffics with REs
(A) Schematic diagram of MyoVb and its association with REs via Rab11/Rab11-FIP2.
(B) Cultured hippocampal neurons (DIV19) were fixed and immunolabeled for endogenous MyoVb and PSD-95 (left). Recycling endosomes (REs) were labeled by Alexa 647-transferrin uptake (Alexa-Tf, middle) or TfR-mCherry expression (TfR-mCh, right), followed by MyoVb staining. Colocalization is indicated by yellow arrows. Red arrows indicate REs in dendritic shafts that are not associated with MyoVb. Dashed white lines indicate the dendritic outline determined by a GFP cell fill. Scale bar, 2 μm.
(C-D) Hippocampal neurons expressing TfR-mCh and GFP-MyoVb FL (C) or GFP-MyoVb ΔC (D) and were imaged over time. Red arrows in (C) indicate the coordinated movement of GFP-MyoVb FL and TfR-mCh into and out of the spine head in two examples (C1, C2). Green arrows in (D) indicate the lack of correlated movement between GFP-MyoVb ΔC and TfR-mCh. Time is indicated in min:sec. Scale bars, 2 μm. See Movies S1-S3.
(E) Means ± SEM of the correlation coefficient between GFP-MyoVb FL or GFP-MyoVb-ΔC and TfR-mCh over time. n = 31 spines from 3 neurons for each; p<0.001 for all time points.