Phosphorylation negatively regulates exosome mediated secretion of cryAB in glioma cells.
Phosphorylation negatively regulates exosome mediated secretion of cryAB in glioma cells.
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DOI：
10.1016/j.bbamcr.2015.11.027
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发表时间：
2016-02
期刊：
影响因子：
--
通讯作者：
Abraham EC
中科院分区：
文献类型：
--
作者：
Kore RA;Abraham EC
外来体介导晶状体蛋白α B（cryAB）的分泌，cryAB是一种具有抗凋亡活性的充分表征的分子伴侣。然而，其包装和分泌的机制仍有待研究。在神经胶质瘤细胞中，尽管cryAB在Ser 59和Ser 45处广泛磷酸化（Ser 19大部分未磷酸化），我们发现大多数分泌的外泌体cryAB是非磷酸化的。短暂的异位表达的黄色荧光蛋白（YFP）标记的三磷酸拟（3-SD）cryAB结构在cryAB缺乏胶质瘤细胞导致形成大的胞质内含物。我们的研究结果表明，模拟磷酸化显着减少cryAB分泌通过外来体。此外，3-SD YFP-cryAB与多泡内体（MVE）和外泌体标志物CD 63或Rab 27（调节MVE胞吐的小GTbR）的共定位减少，表明磷酸化阻止cryAB包装在结合作为外泌体分泌的囊泡中。此外，我们发现阻止cryAB上的O-GlcNAc化也减少了其与CD 63和Rab 27的共定位，导致外泌体分泌减少。因此，我们的研究指出O-GlcNAc酰化和磷酸化的缺乏是参与cryAB通过外泌体的包装和分泌的选择性过程。
Exosomes mediate secretion of crystallin alphaB (cryAB), a well characterized molecular chaperone with anti-apoptotic activity. However, the mechanisms governing its packaging and secretion remained unexplored. In glioma cells, notwithstanding extensive phosphorylation of cryAB at Ser59 followed by Ser45 (Ser19 is largely unphosphorylated), we discovered that the majority of secreted exosomal cryAB is nonphosphorylated. Transient ectopic expression of a yellow fluorescent protein (YFP) tagged triple phosphomimic (3-SD) cryAB construct in cryAB absent glioma cells led to the formation of large cytosolic inclusions. Our findings demonstrate that mimicking phosphorylation significantly reduces cryAB secretion via exosomes. Moreover, decreased colocalization of 3-SD YFP-cryAB with multivesicular endosome (MVE) and exosome marker, CD63 or Rab27, a small GTPase regulating exocytosis of MVEs, suggests that phosphorylation deters packaging of cryAB in vesicles bound for secretion as exosomes. Additionally, we found that preventing O-GlcNAcylation on cryAB also curtailed its colocalization with CD63 and Rab27 resulting in reduced exosomal secretion. Thus, our study points to O-GlcNAcylation and lack of phosphorylation as being the selective processes involved in the packaging and secretion of cryAB via exosomes.
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DOI：
10.1098/rstb.2011.0405
发表时间：
2013-05-05
期刊：
Philosophical transactions of the Royal Society of London. Series B, Biological sciences
影响因子：
--
作者：
Hilton GR;Hochberg GK;Laganowsky A;McGinnigle SI;Baldwin AJ;Benesch JL
通讯作者：
Benesch JL
影响因子：
4.4
作者：
Bajramovic, JJ;Plomp, AC;van Noort, JM
通讯作者：
van Noort, JM
影响因子：
4.8
作者：
Launay, Nathalie;Tarze, Agathe;Lilienbaum, Alain
通讯作者：
Lilienbaum, Alain
影响因子：
4
作者：
Fitzner, Dirk;Schnaars, Mareike;Simons, Mikael
通讯作者：
Simons, Mikael
影响因子：
4.8
作者：
den Englesman, J;Gerrits, D;Boelens, WC
通讯作者：
Boelens, WC