Ultrastructural analysis of the distribution of ACA in migrating cells. (A) Mosaic of hyperbaric freeze EM images displaying an entire migrating ACA-YFP/aca⁻ cell. (B–I) Immunogold EM images depicting the distribution of ACA-YFP in various cellular compartments. m, mitochondria; n, nucleus; c, centriole; PM, plasma membrane. See text for details.