Osteosarcoma cells. Immunofluorescence light micrograph of human osteosarcoma cells responding to a drug and stained to show cell proteins and organelles. These cells are responding to a drug (clotrimazole) that induces energy starvation. Here, membrane ruffles (green, stained actin) have formed on the cells, counter-stained for PACS2 (red) and galactose-containing proteins (PA, blue). PACS2 is a sorting protein that controls the endoplasmic reticulum (ER)-mitochondria communication system. Magnification: x1030 when printed at 10 centimetres wide.