Rabip4’ functions in distribution of lysosomes.

<p>The indicated cell lines were screened for expression of rabip4s by Western blot (<b>A</b>). HEK293T cells were transfected with siRNA against rabip4s and three days later processed for Western blot with antibodies against rabip4s and actin as a loading control, followed by Alexa680-conjugated secondary antibody. siRNA induced an >90% reduction of both rabip4’ and rabip4 isoforms (<b>B</b>). In parallel, cells were labeled for immunoflourescence with monoclonal antibodies against CD63, LAMP-1, CI-MPR, and TfR. LAMP-1 was counterstained with Alexa 594-, while CD63, CI-MPR, and TfR with Alexa 488-labeled secondary antibodies. Nuclei were stained with DAPI. Images represent projections of confocal Z-stacks. Asterisks denote plasma membrane protrusions, enriched in CD63 and LAMP-1, induced by depletion of rabip4s. Scale bar, 10 µm (<b>C</b>).