Department of Orthopaedic Surgery, New York University Grossman School of Medicine, New York, New York, USA.
Department of Endocrinology, the Affiliated Hospital of Qingdao University, Qingdao, China.
Biosci Trends. 2023 May 15;17(2):126-135. doi: 10.5582/bst.2023.01022. Epub 2023 Mar 9.
Gaucher disease (GD), one of the most common lysosomal storage diseases, is caused by GBA1 mutations resulting in defective glucocerebrosidase (GCase) and consequent accumulation of its substrates β-glucosylceramide (β-GlcCer). We reported progranulin (PGRN), a secretary growth factor-like molecule and an intracellular lysosomal protein was a crucial co-factor of GCase. PGRN binds to GCase and recruits Heat Shock Protein 70 (Hsp70) to GCase through its C-terminal Granulin (Grn) E domain, termed as ND7. In addition, both PGRN and ND7 are therapeutic against GD. Herein we found that both PGRN and its derived ND7 still displayed significant protective effects against GD in Hsp70 deficient cells. To delineate the molecular mechanisms underlying PGRN's Hsp70-independent regulation of GD, we performed a biochemical co-purification and mass spectrometry with His-tagged PGRN and His-tagged ND7 in Hsp70 deficient cells, which led to the identification of ERp57, also referred to as protein disulfide isomerase A3 (PDIA3), as a protein that binds to both PGRN and ND7. Within type 2 neuropathic GD patient fibroblasts L444P, bearing GBA1 L444P mutation, deletion of ERp57 largely abolished the therapeutic effects of PGRN and ND7, as manifested by loss of effects on lysosomal storage, GCase activity, and β-GlcCer accumulation. Additionally, recombinant ERp57 effectively restored the therapeutic effects of PGRN and ND7 in ERp57 knockout L444P fibroblasts. Collectively, this study reports ERp57 as a previously unrecognized binding partner of PGRN that contributes to PGRN regulation of GD.
戈谢病（GD）是最常见的溶酶体贮积病之一，由 GBA1 突变引起，导致葡萄糖脑苷脂酶（GCase）缺陷，随后其底物β-葡萄糖脑苷脂（β-GlcCer）积累。我们报道了颗粒体蛋白（PGRN），一种分泌型生长因子样分子和细胞内溶酶体蛋白，是 GCase 的关键辅因子。PGRN 与 GCase 结合，并通过其 C 端 Granulin（Grn）E 结构域将热休克蛋白 70（Hsp70）募集到 GCase 上，称为 ND7。此外，PGRN 和 ND7 均对 GD 具有治疗作用。在此，我们发现 PGRN 及其衍生的 ND7 在 Hsp70 缺失的细胞中对 GD 仍具有显著的保护作用。为了阐明 PGRN 对 GD 的 Hsp70 非依赖性调节的分子机制，我们在 Hsp70 缺失的细胞中用 His 标记的 PGRN 和 His 标记的 ND7 进行了生化共纯化和质谱分析，这导致鉴定了 ERp57，也称为蛋白二硫键异构酶 A3（PDIA3），作为与 PGRN 和 ND7 结合的蛋白质。在携带 GBA1 L444P 突变的 2 型神经 GD 患者成纤维细胞 L444P 中，ERp57 的缺失极大地消除了 PGRN 和 ND7 的治疗作用，表现为对溶酶体贮积、GCase 活性和β-GlcCer 积累的作用丧失。此外，重组 ERp57 有效地恢复了 ERp57 敲除 L444P 成纤维细胞中 PGRN 和 ND7 的治疗作用。总之，这项研究报告 ERp57 是 PGRN 的一个以前未被识别的结合伙伴，有助于 PGRN 对 GD 的调节。
