Cover figure courtesy of Virginia C. Broudy, "Review: Stem Cell Factor and Hematopoiesis." Binding of stem cell factor induces internalization of the stem cell factor-c-kit receptor complex. The human erythroleukemia cell line OCIM1 was treated with or without stem cell factor for 30 minutes at 37°C and stained with an anti-c-kit receptor monoclonal antibody to detect cell surface c-kit receptor (left panels, green fluorescence) or cell surface plus cytoplasmic c-kit receptor (right panels, green fluorescence and punctate yellow fluorescence). The nuclei were counterstained with propidium iodide and appear orange.