BAG3 regulates the specificity of the recognition of specific MAPT species by NBR1 and SQSTM1.
BAG3 regulates the specificity of the recognition of specific MAPT species by NBR1 and SQSTM1.
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BAG3 调节 NBR1 和 SQSTM1 识别特定 MAPT 物种的特异性。
DOI：
10.1101/2023.02.08.527546
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Johnson,GailVW
中科院分区：
文献类型：
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作者：
Lin,Heng;Sandkuhler,Sarah;Dunlea,Colleen;King,DarronH;Johnson,GailVW
巨自噬/自噬受体对于通过选择性自噬识别和清除特定货物是必不可少的，这对于维持MAPT蛋白稳态是必不可少的。以前的研究表明，不同的自噬受体在指导不同种类的MAPT自噬，但其潜在的机制还没有得到充分的研究。在这里，我们研究了自噬受体NBR 1和SQSTM 1如何与特定形式的MAPT差异相关。在原代神经元中，与SQSTM 1耗竭不同，NBR 1耗竭显著增加磷酸化MAPT水平。使用纯化蛋白的体外结合试验证实了相互作用的特异性。我们提供了直接的证据，共分子伴侣BAG 3促进优先协会的NBR 1与单体MAPT和SQSTM 1与寡聚MAPT。使用体外亲和分离测定，我们表明，SQSTM 1仅结合单体MAPT时，BAG 3是不存在的，并未能结合时，BAG 3存在。NBR 1的情况正好相反;它与单体MAPT的结合依赖于BAG 3的存在。有趣的是，在阿尔茨海默病脑中，NBR 1与BAG 3的关联显著降低。在小鼠模型中，神经细胞中BAG 3的消融破坏了NBR 1与磷酸化MAPT的结合，并导致磷酸化和寡聚MAPT水平增加。总的来说，我们的研究结果揭示了BAG 3在调节选择性自噬受体靶向不同种类的MAPT的特异性中的新作用，并提供了令人信服的证据，即BAG 3在维持MAPT蛋白质稳态中起关键作用。转运所需的内体分选复合物; GST：谷胱甘肽S-转移酶; MAPT：微管相关蛋白tau; NBR 1：NBR 1，自噬货物受体; NFT：神经元缠结; PMI：死后间隔; SQSTM 1：死骨小体1。
Macroautophagy/autophagy receptors are essential for the recognition and clearance of specific cargos by selective autophagy, which is essential for maintaining MAPT proteostasis. Previous studies have implicated different autophagy receptors in directing distinct species of MAPT to autophagy, but the underlying mechanisms have not been fully investigated. Here we examine how the autophagy receptors NBR1 and SQSTM1 differentially associate with specific forms of MAPT. In primary neurons depletion of NBR1, unlike depletion of SQSTM1, significantly increased phosphorylated MAPT levels. The specificity of the interactions was confirmed using in vitro binding assays with purified proteins. We provide direct evidence that the co-chaperone BAG3 promotes the preferential association of NBR1 with monomeric MAPT and SQSTM1 with oligomeric MAPT. Using an in vitro affinity-isolation assay, we show that SQSTM1 only binds to monomeric MAPT when BAG3 is absent and fails to bind when BAG3 is present. The opposite is true of NBR1; its association with monomeric MAPT was dependent on the presence of BAG3. Interestingly, in Alzheimer disease brain the association of NBR1 with BAG3 was significantly decreased. In a mouse model, ablation of BAG3 in neural cells disrupted the association of NBR1 with phosphorylated MAPT and led to increased levels of phosphorylated and oligomeric MAPT. Overall, our results uncover a novel role for BAG3 in regulating the specificity of selective autophagy receptors in targeting different species of MAPT and provide compelling evidence that BAG3 plays a key role in maintaining MAPT proteostasis.Abbreviations:AD: Alzheimer disease; BAG3: BCL2-associated athanogene 3; BSA: bovine serum albumin; CERAD: Consortium to Establish a Registry for Alzheimer’s Disease; ESCRT: endosomal sorting complexes required for transport; GST: glutathione S-transferases; MAPT: microtubule-associated protein tau; NBR1: NBR1, autophagy cargo receptor; NFT: neurofibrillary tangles; PMI: postmortem interval; SQSTM1: sequestosome 1.