RACK1 localizes on RNA transport granules in cortical neurons.

<p><b>A</b>, RACK1 appears in granular forms in rat cortical neurons immunostained with anti-RACK1(<i>green</i>) and DAPI (<i>blue</i>). Scale bar 20 µm. <i>Enlarged view</i> indicates neurite of cortical cells. <b>B</b>, RACK1 also appears in granular forms <i>in vivo</i>. Hippocampal tissue of adult mouse immunostained with RACK1 (<i>green</i>). <i>Enlarged view</i> shows the soma of neurons. <i>Arrows</i> indicate the granules stained by RACK1 antibody. Scale bar 20 µm. <b>C</b>, RACK1 colocalizes with endogenous ZBP1 transport RNPs. Cortical neurons were immunostained with RACK1 (<i>red</i>) and ZBP1 (<i>green</i>) antibodies. Scale bar 40 µm. <i>Arrows</i> in enlarged images indicate granules where RACK1 co-localizes with endogenous ZBP1 along neurites. <b>D</b>, RACK1 and GFP-ZBP1 co-localize on transport RNPs of GFP-ZBP1 transfected neurons. Cortical cells were transfected with GFP-ZBP1 cDNA and after 24 hours fixed and processed for anti-RACK1. The <i>arrows</i> in e<i>nlarged view (</i><b><i>a</i></b><i>)</i> indicate the granules where GFP-ZBP1 and RACK1 colocalize. Scale bar 20 µm.