He Ping, Grotzke Jeff E, Ng Bobby G, Gunel Murat, Jafar-Nejad Hamed, Cresswell Peter, Enns Gregory M, Freeze Hudson H
Human Genetics Program, Sanford Children's Health Research Center, Sanford Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
Department of Immunobiology, Yale University, School of Medicine, New Haven, CT 06520-8011, USA.
Glycobiology. 2015 Aug;25(8):836-44. doi: 10.1093/glycob/cwv024. Epub 2015 Apr 21.
N-Glycanase 1, encoded by NGLY1, catalyzes the deglycosylation of misfolded N-linked glycoproteins retrotranslocated into the cytosol. We identified nine cases with mutations in NGLY1. The patients show developmental delay, seizures, peripheral neuropathy, abnormal liver function and alacrima (absence of tears). The mutations in NGLY1 resulted in the absence of N-glycanase 1 protein in patient-derived fibroblasts. Applying a recently established cellular deglycosylation-dependent Venus fluorescence assay, we found that patient fibroblasts had dramatically reduced fluorescence, indicating a pronounced reduction in N-glycanase enzymatic activity. Using this assay, we could find no evidence of other related activities. Our findings reveal that NGLY1 mutations destroy both N-glycanase 1 protein and enzymatic activity.
由NGLY1编码的N-聚糖酶1催化逆向转运到胞质溶胶中的错误折叠的N-连接糖蛋白的去糖基化反应。我们鉴定出9例NGLY1突变病例。这些患者表现出发育迟缓、癫痫、周围神经病变、肝功能异常和无泪（泪液缺乏）。NGLY1中的突变导致患者来源的成纤维细胞中缺乏N-聚糖酶1蛋白。应用最近建立的细胞去糖基化依赖性金星荧光测定法，我们发现患者成纤维细胞的荧光显著降低，表明N-聚糖酶的酶活性明显降低。使用该测定法，我们没有发现其他相关活性的证据。我们的研究结果表明，NGLY1突变会破坏N-聚糖酶1蛋白和酶活性。
