Fig. 2.

Expression of dominant-negative Rab5A abolishes the somatodendritic polarity of glutamate receptors. (A and B) Rat hippocampal neurons were cotransfected at DIV4 with plasmids encoding GluR1-GFP, SEP-GluR2, NR2A-GFP, NR2B-GFP, or mGluR1-GFP together with plasmids encoding mCherry (mCh)-tubulin (control) (A) or dominant-negative mCherry-Rab5A-S34N (B). Fixed neurons were immunostained at DIV9 for GFP and AnkG and were imaged by confocal microscopy. Images are shown in negative grayscale. Arrows mark the position of the AIS, and arrowheads indicate the axon. (Scale bar: 20 μm.) (C) Dendrite/axon polarity indexes for glutamate receptors are represented as the mean ± SEM from 10 neurons in at least three independent experiments such as those shown in A and B. *P < 0.01 per Student’s t test. Notice that expression of mCherry-Rab5A-S34N abrogates the somatodendritic polarity of all the glutamate receptor proteins.