A Novel Functional Missense Mutation p.T219A in Type 1 Gaucher's Disease.

BACKGROUND: Gaucher's disease (GD) is an autosomal recessive disorder caused by a deficiency of acid ß-glucosidase (glucocerebrosidase [GBA]) that results in the accumulation of glucocerebroside within macrophages. Many mutations have been reported to be associated with this disorder. This study aimed to discover more mutations and provide data for the genetic pattern of the gene, which will help the development of quick and accurate genetic diagnostic tools for this disease. METHODS: Genomic DNA was obtained from peripheral blood leukocytes of the patient and Sanger sequencing is used to sequence GBA gene. Sequence alignments of mammalian ß-GBA (GCase) and three-dimensional protein structure prediction of the mutation were made. A construct of this mutant and its compound heterozygous counterpart were used to measure GCase in vitro. RESULTS: GCase is relatively conserved at p.T219A. This novel mutation differs from its wild-type in structure. Moreover, it also causes a reduction in GCase enzyme activity. CONCLUSION: This novel mutation (c.655A>G, p.T219A) is a pathogenic missense mutation, which contributes to GD.

[Pathogenic mechanism and therapies for Gaucher's disease].

Gaucher's disease (GD) also named glucocerebroside lipidosis, is the most common kind of 1ysosomal storage disorder. It results from an autosomal recessive deficiency of the lysosomal enzyme acid ß-glucosidase/ ß-glucocerebrosidase (GBA), which is responsible for hydrolysis of glucocerebroside/glucosylceramide (GlcCer) into glucose and ceramide. Absent or reduced enzymatic activity of GBA leads to multisystemic accumulation of GlcCer in mononuclear phagocyte system and various tissues, such as brain, liver, spleen and so on, causing brain injury, liver splenomegaly, bone damage, the reduction of blood cells and individual growth retardation. GD type I could be treated by enzyme replacement therapy (ERT), but GD types II and III have not effective treatment. In this review, we summarize the recent progress on pathogenic mechanism and therapies in GD.

Mammalian sterile 20-like kinase 1/2 inhibits the Wnt/ß-catenin signalling pathway by directly binding casein kinase 1ε.

The Hippo signalling pathway can suppress the Wnt/ß-catenin signalling pathway through the last downstream effectors YAP (Yes-associated protein)/TAZ (tafazzin). MST (mammalian sterile 20-like kinase) 1 functions as the upstream kinase of the Hippo pathway, and CK1ε (casein kinase 1ε) plays roles in the up-stream signal transduction of the Wnt/ß-catenin pathway. In the present study, using tandem affinity purification and MS analysis, CK1ε was identified as a novel partner of MST1. Further analysis showed that the interaction between MST1 and CK1ε was mediated by their kinase domains and enhanced by the activation of MST1. To exclude the interference of the phosphorylated YAP/TAZ, the transduction from MST1 to YAP/TAZ was blocked using anti-WW45 shRNA. In the sh-WW45 cells, MST1 still inhibited the Wnt3A-induced phosphorylation of DVL2 (dishevelled 2) and Wnt/ß-catenin signalling by disturbing the interaction of DVL2 and CK1ε. The growth-suppressive effect of MST1 in the presence of Wnt3A was effectively relieved by the downstream activation of the Wnt/ß-catenin pathway. Moreover, MST2, the close homologue of MST1, also displayed the similar function in suppressing the Wnt/ß-catenin pathway. Therefore the results of the present study revealed that, in addition to the phosphorylated YAP/TAZ, the Hippo pathway can suppress the Wnt/ß-catenin pathway directly through MST1/2.