Expression of Wild Type and Truncated Myocilins in Trabecular Meshwork Cells: their Subcellular Localization.

Hur, Won Hee; Kee, Chang Won

Original Article

Journal of the Korean Ophthalmological Society 2003;44(4):955-964.
Published online April 1, 2003.

Expression of Wild Type and Truncated Myocilins in Trabecular Meshwork Cells: their Subcellular Localization.

Department of Ophthalmology, Samsung Medical Center Sungkyunkwan University, College of Medicine, Korea. cwkee@smc.samsung.co.kr

섬유주 세포 내에서 나타나는 Myocilin의 발현 양상

허원희 ( Won Hee Hur ) , 기창원 ( Chang Won Kee )

Abstract

PURPOSE
To investigate subcellular localizations of wild type myocilin and trunctated (Q368X) myocilin in cultured human trabecular meshwork (TM) cells. METHODS: GFP and GFP tagged truncated myocilin, full-length myocilin, and stromelysin were expressed in TM cells using adenoviral vectors, and their secretory properties were examined by western blotting. To determine the subcellular localizations of myocilins, cellular organelles of the infected TM cells were stained with antibodies or orgenelle specific fluorescent indicators and examined under confocal microscope. RESULTS: Wild type myocilin was expressed as discrete fine vesicles in the perinuclear region of TM cells as well as in ER, but not in microtubules or mitochondria. Colocalization of wild type and truncated myocilin, indicative of in vivo interaction of the proteins, was also observed in cells co-expressing the proteins. Truncated myocilin was found to be accumulated as aggregates in ER, and inhibited the secretion of normal myocilin. CONCLUSIONS: Our result suggests that intracellular accumulation of truncated myocilin may cause a dysfunction of the cells, resulting in alterations in structural compartmentalization of trabecular ECM and obstruction of aqueous outflow.

Key Words: Adenoviral vector;Myocilin;Subcellular localization;Trabecular meshwork cell