Journal of Glycobiology
Open Access

Glycosylation regulates CD38 assembly on the cell surface

Glycobiology World Congress

August 10-12, 2015 Philadelphia, USA

Miki Hara-Yokoyama

Scientific Tracks Abstracts: J Glycobiol

Abstract :

Many proteins have their functions on the cell membranes or organelle membranes. To understand the function on the
membranes, it is important to elucidate the cell-surface assembly. The leukocyte cell-surface antigen CD38 is a type II
transmembrane glycoprotein and has four N-glycosylation sites. CD38 is the major NAD+ glycohydrolase in mammals and its
ecto-enzyme activity is involved in calcium mobilization. CD38 also acts as a lipid raft-dependent signalling molecule to promote
cell proliferation or death. CD38 forms a tetramer on the cell surface but the structural basis and the functional significance of
tetramerization have remained unexplored. We identified the interfaces contributing to the homophilic interaction of mouse
CD38 by site-specific crosslinking on the cell surface with an expanded genetic code based on a crystallographic analysis.
A combination of the three interfaces enables CD38 to tetramerize: One interface involving the juxtamembrane α-helix is
responsible for the formation of the core dimer which is further dimerized via the other two interfaces. This dimerization of
dimers underlies the catalytic activity and the localization of CD38 in lipid rafts. The N-linked glycosylation sites are found to
be located in strategic positions to prevent further self-association of the tetramer. Accordingly, the glycosylation is likely to
ensure the function of CD38 by regulating the cell-surface assembly.

Biography :

Miki Hara-Yokoyama has received her PhD in 1986 at the Department of Biophysics and Biochemistry, Faculty of Science, Tokyo University. She worked at the
Department of Physiology in Nihon University School of Dentistry at Matsudo as a Research Associate (1986-1995) and as a Lecturer (1995-2001). Then, she moved
to the Department of Biochemistry in Tokyo Medical and Dental University (TMDU) and worked as a Lecturer (2001-2004). Currently, she is an Associate Professor
of the department. Her research interests include regulation of protein assembly on the membrane by glycosylation or lipid-environment.