Altered Rhythm of Photoreceptor Outer Segment Phagocytosis in β5 Integrin Knockout Mice.

In the retina photoreceptor and retinal pigment epithelial cells (RPE cells) are in close contact. The outer segment portions of photoreceptors consist of stacked membranous disks containing the phototransduction machinery. These disks are permanently produced thereby lengthening outer segments. To maintain constant outer segment length photoreceptors eliminate their most aged tips by daily shedding (Young, 1967). [ABSTRACT FROM AUTHOR]