Calcium dysregulation potentiates wild-type myocilin misfolding: implications for glaucoma pathogenesis.
Calcium dysregulation potentiates wild-type myocilin misfolding: implications for glaucoma pathogenesis.
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钙失调增强了野生型心肌蛋白错误折叠：对青光眼发病机制的影响。
DOI：
10.1007/s00775-022-01946-3
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发表时间：
2022-09
影响因子：
3
通讯作者：
Lieberman, Raquel L.
中科院分区：
文献类型：
--
作者：
Saccuzzo, Emily G.;Martin, Mackenzie D.;Hill, Kamisha R.;Minh Thu Ma;Ku, Yemo;Lieberman, Raquel L.
肌球蛋白从小梁网细胞分泌到对维持眼内压至关重要的上皮细胞外基质。在myocilin olfactomedin结构域（OLF）中发现的错义突变导致细胞内myocilin错误折叠，并导致早发性青光眼的遗传形式。OLF结构域包含一个独特的内部异源双核钙位点。在这里，我们测试了钙调节异常导致野生型（WT）肌钙蛋白错误折叠的假设，这让人想起在疾病变体中观察到的情况。使用两个细胞模型表达WT myocilin，我们表明，Ca 2 + ATP酶通道阻滞剂毒胡萝卜素抑制WT myocilin分泌。细胞内WT肌钙蛋白至少部分不溶，并聚集在内质网（ER）中，用淀粉样蛋白染料染色呈阳性。通过比较野生型肌细胞素的效果，从头分泌能力的Ca 2 +-免费的变体D478 S，我们辨别，非分泌野生型肌细胞素是由于最初的钙失调，并进一步增强所产生的ER应力。在大肠在大肠杆菌中，钙的消耗导致错误折叠的分离的WT OLF的表达，但D478 S变体仍然作为折叠的单体产生。用毒胡萝卜素处理表达由D478 S和疾病变体P370 L或Y 437 H组成的双突变体的细胞促进其错误折叠和聚集，证明D478 S纠正分泌缺陷的限制。两者合计，异双核钙网站是一个合理的折叠myocilin的责任。我们的研究提示WT myocilin错误折叠可能广泛地促进脑胶质瘤相关的ER应激的分子机制。
Myocilin is secreted from trabecular meshwork cells to an eponymous extracellular matrix that is critical for maintaining intraocular pressure. Missense mutations found in the myocilin olfactomedin domain (OLF) lead to intracellular myocilin misfolding and are causative for the heritable form of early-onset glaucoma. The OLF domain contains a unique internal, hetero-dinuclear calcium site. Here we tested the hypothesis that calcium dysregulation causes wild-type (WT) myocilin misfolding reminiscent of that observed for disease variants. Using two cellular models expressing WT myocilin we show that the Ca2+ ATPase channel blocker thapsigargin inhibits WT myocilin secretion. Intracellular WT myocilin is at least partly insoluble and aggregated in the endoplasmic reticulum (ER), and stains positively with an amyloid dye. By comparing the effect of WT myocilin to that of a de novo secretion-competent Ca2+-free variant D478S, we discern that non-secretion of WT myocilin is due initially to calcium dysregulation, and is potentiated further by resultant ER stress. In E. coli, depletion of calcium leads to expression of misfolded isolated WT OLF but the D478S variant is still produced as a folded monomer. Treatment of cells expressing a double mutant composed of D478S and either disease variants P370L or Y437H with thapsigargin promotes its misfolding and aggregation, demonstrating the limits of D478S to correct secretion defects. Taken together, the heterodinuclear calcium site is a liability for proper folding of myocilin. Our study suggests a molecular mechanism by which WT myocilin misfolding may contribute broadly to glaucoma-associated ER stress.
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影响因子：
4.8
作者：
Hill, Shannon E.;Kwon, Michelle S.;Lieberman, Raquel L.
通讯作者：
Lieberman, Raquel L.
影响因子：
4.3
作者：
Casanova, D;Alemany, P;Alvarez, S
通讯作者：
Alvarez, S
影响因子：
4
作者：
Kennan, AM;Mansergh, FC;Farrar, GJ
通讯作者：
Farrar, GJ
影响因子：
4
作者：
Burns, J. Nicole;Orwig, Susan D.;Harris, Julia L.;Watkins, J. Derrick;Vollrath, Douglas;Lieberman, Raquel L.
通讯作者：
Lieberman, Raquel L.
影响因子：
3.7
作者：
Kopec KO;Lupas AN
通讯作者：
Lupas AN