Sub-RPE deposits might be related to defective ubiquitin-dependent proteolysis

Abstract

Sub-retinal pigment epithelium (RPE) deposits can be distinguished by their location, morphology and histochemical properties. Soft drusen and basal laminar deposit (BLD), especially, are considered of major importance in the pathogenesis of disciform age-related macular degeneration, and it has been speculated that certain components within these structures might be responsible for subretinal neovascularization. At present, however, not even the processes underlying the formation of drusen or BLD are known. Ubiquitin (Ub) is a member of the stress protein family that has been shown to be involved in the non-lysosomal degradation process of abnormal proteins, especially in neurodegenerative diseases. Using immunohistochemical methods, we investigate the human retina and RPE and in particular sub-RPE deposits for the presence and distribution of Ub and related enzymes.