Protease activities in cultured beef lens epithelial cells peak and then decline upon progressive passage

Eisenhauer, Donald A.; Berger, Joseph J.; Peltier, Cynthia Z.; Taylor, Allen

doi:10.1016/s0014-4835(88)80014-9

Cited by 32 publications

(9 citation statements)

References 45 publications

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“…An “autocatalytic” decline in control of protein quality is also indicated by observation that whereas initiation of lens early opacities takes decades, progression to debilitating cataracts frequently occurs during just a few years. This age‐related accumulation and acceleration toward lesion is consistent with the age‐related decline in UPP capability, particularly the proteolytic component of the UPP (36, 77). The accumulation of protein aggregates that contain oxidatively modified proteins with ubiquitin conjugates also disrupt function in many other cell types, including premature aging syndromes, age‐related diseases such as age‐related maculopathy, the amyloid diseases, including Alzheimer's, Parkinson's and ALS, ataxias and other neurodegenerative disorders, diabetes, and some cancers (24, 64, 66, 74, 78, 79).…”

Section: Discussionsupporting

confidence: 72%

Selectivity of the ubiquitin pathway for oxidatively modified proteins: relevance to protein precipitation diseases

et al. 2005

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There is now consensus that the accumulation of oxidatively modified proteins is cytotoxic and causally related to several age-related diseases, including the amyloid diseases and age-related cataracts. There is also general agreement that proteolytic pathways provide a quality control mechanism to limit accumulation of damaged proteins. Although many researchers assume that the ubiquitin pathway is involved in recognition and proteolytic removal of oxidatively modified proteins, which are produced upon cellular stress, there has been no direct evidence to support this hypothesis. In this work, we used a novel proteolysis-resistant ubiquitin variant to demonstrate that ubiquitin conjugates isolated from oxidatively stressed mammalian cells are enriched 3.3-15-fold for oxidatively modified proteins and that failure to execute ubiquitin-dependent proteolysis renders various cell types more susceptible to oxidative stress-related cytotoxicity. These results were corroborated using several inhibitors of the ubiquitin proteasome pathway, including PS-341, an anticancer drug in clinical use. Taken together the data indicate that the ubiquitin proteolytic pathway recognizes and removes oxidatively modified proteins, and that failure of this system, as occurs upon aging or stress, may be involved in and exacerbate cytotoxicity and age-related syndromes in which accumulation of ubiquitinated and oxidatively modified proteins has an etiologic role.

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Section: Discussionsupporting

confidence: 72%

Selectivity of the ubiquitin pathway for oxidatively modified proteins: relevance to protein precipitation diseases

et al. 2005

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“…The cysteine protease cathepsin B has been identified in rat and guinea-pig lens [24,18], bovine iris and ciliary body [27], rat retina [47] and bovine retinal pigment epithelium [22], but its precise localization and function in most ocular tissues is not well known.…”

Section: Discussionmentioning

confidence: 99%

Cathepsin B in the rat eye

Wassélius

Wallin

Abrahamson

et al. 2003

Graefe's Arch Clin Exp Ophthalmol

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“…Cystatin C is an efficient inhibitor of cathepsin B (Abrahamson et al 1986), which is known to be present in the lens (Gorthy & Azari 1987; Eisenhauer et al 1988), although its specific localization has not to our knowledge been published. However, pilot experiments have suggested that cathepsin B in the lens is found exclusively in its epithelium (Wassélius et al 2003), and it is thus a possible target enzyme for cystatin C.…”

Section: Discussionmentioning

confidence: 99%

Cystatin C in the anterior segment of rat and mouse eyes

Wassélius

Håkansson

Abrahamson

et al. 2003

Acta Ophthalmologica Scandinavica

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ABSTRACT.Purpose: Cystatin C is a mammalian cysteine protease inhibitor. This study describes the localization of cystatin C in the anterior segment of normal rat and mouse eyes. Cysteine proteases play an important role in protein degradation (e.g. of photoreceptor outer segments in the retinal pigment epithelium) and the balance between these proteases and their specific inhibitors is therefore of great interest. Methods: Cells containing cystatin C were identified by immunohistochemistry and quantified by ELISA. Messenger RNA levels were analysed by quantitative real-time polymerase chain reaction. Results: Cystatin C is present at biologically significant levels in the corneal epithelium, endothelium and stromal keratinocytes, lens epithelium, epithelial cells in the ciliary processes, aqueous humour and iris stromal cells. In the rat anterior segment, the highest cystatin C concentrations were found in the ciliary epithelium. Conclusions: Cystatin C is present in several cell types and is probably locally produced. The inhibitor is likely to be an important regulator of cysteine proteases in the retinal pigment epithelium, ciliary epithelium, aqueous humour, lens epithelium and in the corneal endothelium and epithelium.

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Protease activities in cultured beef lens epithelial cells peak and then decline upon progressive passage

Cited by 32 publications

References 45 publications

Selectivity of the ubiquitin pathway for oxidatively modified proteins: relevance to protein precipitation diseases

Selectivity of the ubiquitin pathway for oxidatively modified proteins: relevance to protein precipitation diseases

Cathepsin B in the rat eye

Cystatin C in the anterior segment of rat and mouse eyes

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