Sulfation of glycosaminoglycans depends on the catalytic activity of lithium-inhibited phosphatase BPNT2 in vitro.
Sulfation of glycosaminoglycans depends on the catalytic activity of lithium-inhibited phosphatase BPNT2 in vitro.
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DOI：
10.1016/j.jbc.2021.101293
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发表时间：
2021-11
期刊：
影响因子：
--
通讯作者：
York JD
中科院分区：
文献类型：
--
作者：
Eisele BS;Luka Z;Wu AJ;Yang F;Hale AT;York JD
高尔基体驻留的二磷酸核苷酸酶2(BPNT2)是镁依赖的、锂抑制的磷酸酶家族中的一个成员，该家族共享一个三维结构基序，直接配位金属结合来影响磷酸水解酶。BPNT2催化3‘-磷酸腺苷-5’-磷酸的分解，这是糖胺聚糖(GAG)硫化的副产物。在小鼠中，BPNT2的KO导致骨骼异常，因为GAG硫化受损，特别是软骨素-4-硫酸盐，这是正常的细胞外基质发育的关键。BPNT2的突变也被发现是人类软骨发育不良疾病的基础。BPNT2缺失损害硫酸盐化的确切机制尚不清楚。在这里，我们使用小鼠胚胎成纤维细胞(MEF)来验证BPNT2的催化活性是体外GAG硫化所必需的假设。我们表明，催化死亡的Bpnt2构建体(D108A)不能修复细胞内或分泌的硫酸盐GAG的损伤，包括Bpnt2-KO MEF中存在的软骨素-4-硫酸盐减少。我们还证明了催化部位附近的Bpnt2错义突变，已知会导致人类软骨发育不良，概括了MEF培养中总体Gag硫化和软骨素-4-硫化的缺陷。我们进一步证明，用锂(一种常见的精神药物)治疗MEF可以抑制GAG硫酸盐化，并且这种作用依赖于BPNT2的存在。综上所述，这项工作证明了一种被锂有效抑制的酶的催化活性可以调节Gag硫酸盐化，从而调节细胞外基质的组成，从而揭示了对锂药理学的新见解。
Golgi-resident bisphosphate nucleotidase 2 (BPNT2) is a member of a family of magnesium-dependent, lithium-inhibited phosphatases that share a three-dimensional structural motif that directly coordinates metal binding to effect phosphate hydrolysis. BPNT2 catalyzes the breakdown of 3′-phosphoadenosine-5′-phosphate, a by-product of glycosaminoglycan (GAG) sulfation. KO of BPNT2 in mice leads to skeletal abnormalities because of impaired GAG sulfation, especially chondroitin-4-sulfation, which is critical for proper extracellular matrix development. Mutations in BPNT2 have also been found to underlie a chondrodysplastic disorder in humans. The precise mechanism by which the loss of BPNT2 impairs sulfation remains unclear. Here, we used mouse embryonic fibroblasts (MEFs) to test the hypothesis that the catalytic activity of BPNT2 is required for GAG sulfation in vitro. We show that a catalytic-dead Bpnt2 construct (D108A) does not rescue impairments in intracellular or secreted sulfated GAGs, including decreased chondroitin-4-sulfate, present in Bpnt2-KO MEFs. We also demonstrate that missense mutations in Bpnt2 adjacent to the catalytic site, which are known to cause chondrodysplasia in humans, recapitulate defects in overall GAG sulfation and chondroitin-4-sulfation in MEF cultures. We further show that treatment of MEFs with lithium (a common psychotropic medication) inhibits GAG sulfation and that this effect depends on the presence of BPNT2. Taken together, this work demonstrates that the catalytic activity of an enzyme potently inhibited by lithium can modulate GAG sulfation and therefore extracellular matrix composition, revealing new insights into lithium pharmacology.
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DOI：
10.1007/978-1-61737-960-4_15
发表时间：
2011
期刊：
Methods in molecular biology (Clifton, N.J.)
影响因子：
--
作者：
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通讯作者：
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DOI：
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发表时间：
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期刊：
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影响因子：
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作者：
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通讯作者：
York JD
影响因子：
11.4
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2
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