Fig. 5.

Actin polymerization is required to form the lysosomal synapse. (A–D) J774 cells were incubated with Alexa546–agLDL for 1 h in the presence of DMSO (A,B) or 1 μM LatA (C,D), labeled with Alexa488–CtB on ice and fixed with 3% PFA to allow compartment visualization. Membrane invaginations could be seen at sites of contact between control DMSO treated macrophages and agLDL (arrow, A,B), indicative of compartment formation. Cells treated with LatA did not form membrane invaginations at sites of contact with agLDL (C,D). (E) Quantification of total integrated CtB fluorescence colocalized with agLDL in DMSO- and LatA-treated macrophages. Data compiled from three independent experiments (n=53 fields per condition). ***P≤0.001 Student's t-test. Error bars represent the standard error of the mean.