Keratin 1 Plays a Critical Role in Golgi Localization of Core 2 N-Acetylglucosaminyltransferase M via Interaction with Its Cytoplasmic Tail

• DOI: 10.1074/jbc.m114.618702
• Publication Date: 2015-01-21T03:10:06Z
• Authors: Armen Petrosyan; Mohamed F. Ali; Pi-Wan Cheng
• Keywords: Brefeldin A; HEK 293 cells

Core 2 N-acetylglucosaminyltransferase 2/M (C2GnT-M) synthesizes all three β6GlcNAc branch structures found in secreted mucins. Loss of C2GnT-M leads to development colitis and colon cancer. Recently we have shown that targets the Golgi at Giantin site is recycled by binding non-muscle myosin IIA, a motor protein, via cytoplasmic tail (CT). But how this enzyme retained not known. Proteomics analysis identifies keratin type II cytoskeletal 1 (KRT1) as protein pulled down with anti-c-Myc antibody or CT from lysate Panc1 cells expressing bC2GnT-M tagged c-Myc. Yeast two-hybrid shows rod domain KRT1 interacts directly WKR6 motif CT. Knockdown does affect morphology but increases interaction IIA its transportation endoplasmic reticulum, ubiquitination, degradation. During recovery after brefeldin A treatment, forms complex before KRT1, demonstrating CT-mediated sequential events targeting retention C2GnT-M. In HeLa transiently C2GnT-M-GFP, knockdown leaves outside Golgi, resulting formation sialyl-T antigen. Interaction was also detected goblet human epithelial tissue primary culture colonic cells. The results indicate glycosylation thus function glycoconjugates can be regulated helps retain glycosyltransferase Golgi.