bioRxiv preprint doi: https://doi.org/10.1101/743914; this version posted August 24, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 Cross-talks of glycosylphosphatidylinositol biosynthesis with glycosphingolipid biosynthesis 2 and ER-associated degradation 3 4 Yicheng Wang1,2, Yusuke Maeda1, Yishi Liu3, Yoko Takada2, Akinori Ninomiya1, Tetsuya 5 Hirata1,2,4, Morihisa Fujita3, Yoshiko Murakami1,2, Taroh Kinoshita1,2,* 6 7 1Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan 8 2WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, 9 Japan 10 3Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, 11 School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China 12 4Current address: Center for Highly Advanced Integration of Nano and Life Sciences (G- 13 CHAIN), Gifu University, 1-1 Yanagido, Gifu-City, Gifu 501-1193, Japan 14 15 *Correspondence and requests for materials should be addressed to T.K. (email: 16
[email protected]) 17 18 19 Glycosylphosphatidylinositol (GPI)-anchored proteins and glycosphingolipids interact with 20 each other in the mammalian plasma membranes, forming dynamic microdomains. How their 21 interaction starts in the cells has been unclear. Here, based on a genome-wide CRISPR-Cas9 22 genetic screen for genes required for GPI side-chain modification by galactose in the Golgi 23 apparatus, we report that b1,3-galactosyltransferase 4 (B3GALT4), also called GM1 24 ganglioside synthase, additionally functions in transferring galactose to the N- 25 acetylgalactosamine side-chain of GPI.