Processing and secretion of the N-terminal domain of α-dystroglycan in cell culture media

Saito, Fumiaki; Saito-Arai, Yuko; Nakamura, Ayami; Shimizu, Teruo; Matsumura, Kiichiro

doi:10.1016/j.febslet.2008.01.006

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Volume 582, Issue 3 , Pages 439-444, 6 February 2008

Processing and secretion of the N-terminal domain of α-dystroglycan in cell culture media

Edited by Angel Nebreda

Department of Neurology and Neuroscience, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan

Received 29 November 2007; received in revised form 26 December 2007; accepted 9 January 2008. published online 15 January 2008.

Abstract

α-Dystroglycan (α-DG) plays a crucial role in maintaining the stability of muscle cell membrane. Although it has been shown that the N-terminal domain of α-DG (α-DG-N) is cleaved by a proprotein convertase, its physiological significance remains unclear. We show here that native α-DG-N is secreted by a wide variety of cultured cells into the culture media. The secreted α-DG-N was both N- and O-glycosylated. Finally, a small amount of α-DG-N was detectable in the normal human serum. These observations indicate that the cleavage of α-DG-N is a widespread event and suggest that the secreted α-DG-N might be transported via systemic circulation in vivo.

Abbreviations: DG, dystroglycan, α-DG-N, N-terminal domain of α-dystroglycan, PC, proprotein convertase

Keywords: Dystroglycan, Muscular dystrophy, Processing of protein, Glycosylation, Proprotein convertase