1. Calreticulin activates β1 integrin via fucosylation by fucosyltransferase 1 in J82 human bladder cancer cells
- Author
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Chia-Ying Chu, Wen-Ming Hsu, Chia Hua Chen, Chiung-Nien Chen, Jen Her Lu, Swey Shen Alex Chen, Yi-Chien Lu, Yung-Feng Liao, Chin Chen Pan, Min-Chuan Huang, Cheng-Chi Chang, Tsui Hwa Lin, Hsinyu Lee, Hsin Yi Hsia, Bo Jeng Wang, and Pei Yi Wu
- Subjects
Fucosyltransferase ,biology ,Protein Stability ,Integrin beta1 ,RNA Stability ,Integrin ,Cell Biology ,Fucosyltransferases ,Biochemistry ,Molecular biology ,Urinary Bladder Neoplasms ,Integrin alpha M ,Cell Line, Tumor ,Cancer cell ,Cell Adhesion ,biology.protein ,Humans ,Integrin, beta 6 ,Calreticulin ,Cell adhesion ,Molecular Biology ,Fucosylation - Abstract
Fucosylation regulates various pathological events in cells. We reported that different levels of CRT (calreticulin) affect the cell adhesion and metastasis of bladder cancer. However, the precise mechanism of tumour metastasis regulated by CRT remains unclear. Using a DNA array, we identified FUT1 (fucosyltransferase 1) as a gene regulated by CRT expression levels. CRT regulated cell adhesion through α1,2-linked fucosylation of β1 integrin and this modification was catalysed by FUT1. To clarify the roles for FUT1 in bladder cancer, we transfected the human FUT1 gene into CRT-RNAi stable cell lines. FUT1 overexpression in CRT-RNAi cells resulted in increased levels of β1 integrin fucosylation and rescued cell adhesion to type-I collagen. Treatment with UEA-1 ( Ulex europaeus agglutinin-1), a lectin that recognizes FUT1-modified glycosylation structures, did not affect cell adhesion. In contrast, a FUT1-specific fucosidase diminished the activation of β1 integrin. These results indicated that α1,2-fucosylation of β1 integrin was not involved in integrin–collagen interaction, but promoted β1 integrin activation. Moreover, we demonstrated that CRT regulated FUT1 mRNA degradation at the 3′-UTR. In conclusion, the results of the present study suggest that CRT stabilized FUT1 mRNA, thereby leading to an increase in fucosylation of β1 integrin. Furthermore, increased fucosylation levels activate β1 integrin, rather than directly modifying the integrin-binding sites. Abbreviations: Act-D, actinomycin D; ARE, AU-rich element; ARE-BP, ARE-binding protein; CDS, coding sequence; CMV, cytomegalovirus; CRT, calreticulin; EF1α, elongation factor 1α; FBP1/FUBP1, far-upstream-binding protein 1; FUT, fucosyltransferase; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GnT, N-acetylglucosaminyltransferase; HRP, horseradish peroxidase; LTL, Lotus tetragonolobus lectin; mARE, mutant ARE; NP40, Nonidet P40; PE, phycoerythrin; REMSA, RNA EMSA; UEA-1, Ulex europaeus agglutinin-1
- Published
- 2014