Functional Characterization of the Human Facilitative Glucose Transporter 12 1 (glut12) by Electrophysiological Methods 2

Functional characterization of the human facilitative glucose transporter 12 1 (GLUT12) by electrophysiological methods 2 Short title: Functional characterization of hGLUT12 3 Authors 4 Jonai Pujol-Giménez, Alejandra Pérez, Alejandro Reyes, Donald D.F. Loo and 5 Maria Pilar Lostao 6 Affiliations 7 1 Department of Nutrition, Food Science and Physiology, School of Pharmacy, 8 University of Navarra, Pamplona, Spain; 2 Instituto de Bioquímica y Microbiología, 9 Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile; 3 Department of 10 Physiology, David Geffen School of Medicine at University of California, Los Angeles, 11 California, USA. 12 Corresponding author 13 Maria Pilar Lostao 14 E-mail: [email protected] 15 Phone: 34-948425649 16 Fax: 34-948425740 17 ABSTRACT 18 GLUT12 is a member of the facilitative family of glucose transporters. The goal of this 19 study was to characterize the functional properties of GLUT12, expressed in Xenopus 20 laevis oocytes, using radiotracer and electrophysiological methods. Our results showed 21 that GLUT12 is a facilitative sugar transporter with substrate selectivity: D-glucose≥α22 methyl-D-glucopyranoside(α-MG)>2-deoxy-D-glucose(2-DOG)>D-fructose=D23 galactose. α-MG is a characteristic substrate of the Na/glucose (SGLT) family, and has 24 not been shown to be a substrate of any of the GLUTs. In the absence of sugar, Na 25 Articles in PresS. Am J Physiol Cell Physiol (April 8, 2015). doi:10.1152/ajpcell.00343.2014