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Non-secretion of mutant proteins of the glaucoma gene myocilin in cultured trabecular meshwork cells and in aqueous humor
Journal article   Open access   Peer reviewed

Non-secretion of mutant proteins of the glaucoma gene myocilin in cultured trabecular meshwork cells and in aqueous humor

Nasreen Jacobson, Michael Andrews, Allan R Shepard, Darryl Nishimura, Charles Searby, John H Fingert, Greg Hageman, Robert Mullins, Beverly L Davidson, Young H Kwon, …
Human molecular genetics, Vol.10(2), pp.117-125
01/15/2001
DOI: 10.1093/hmg/10.2.117
PMID: 11152659
url
https://doi.org/10.1093/hmg/10.2.117View
Published (Version of record) Open Access

Abstract

Until recently, very little was known about the molecular mechanisms responsible for the development of glaucoma, a leading cause of blindness worldwide. Mutations in the glaucoma gene myocilin (MYOC, GLC1A) are associated with elevated intraocular pressure and the development of autosomal dominant juvenile glaucoma and a subset of adult-onset glaucoma. MYOC is expressed in the trabecular meshwork (TM), a tissue responsible for drainage of aqueous humor from the eye, and the tissue involved in elevated intraocular pressure associated with glaucoma. To better understand the role of MYOC in glaucoma pathogenesis, we examined the expression of normal and mutant myocilin in cultured ocular (TM) and non-ocular cells as well as in the aqueous humor of patients with and without MYOC glaucoma. Normal myocilin was secreted from cultured cells, but very little to no myocilin was secreted from cells expressing five different mutant forms of MYOC. In addition, no mutant myocilin was detected in the aqueous humor of patients harboring a nonsense MYOC mutation (Q368X). Co-transfection of cultured cells with normal and mutant myocilin led to suppression of normal myocilin secretion. These studies suggest that MYOC glaucoma is due either to insufficient levels of secreted myocilin or to compromised TM cell function caused by congestion of the TM secretory pathway.
Mutation Transfection Cytoskeletal Proteins Glycoproteins - genetics Humans Glycoproteins - metabolism Codon, Nonsense Blotting, Western Aqueous Humor - metabolism Animals Eye Proteins - metabolism Trabecular Meshwork - metabolism Eye Proteins - genetics Glaucoma - metabolism Tumor Cells, Cultured Glaucoma - genetics COS Cells Cell Line, Transformed

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