PEX16 contributions to peroxisome import and metabolism revealed by viable Arabidopsis pex16 mutants.
PEX16 contributions to peroxisome import and metabolism revealed by viable Arabidopsis pex16 mutants.
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可行的拟南芥 pex16 突变体揭示了 PEX16 对过氧化物酶体输入和代谢的贡献。
DOI：
10.1111/jipb.12789
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发表时间：
2019
影响因子：
11.4
通讯作者：
Bartel,Bonnie
中科院分区：
文献类型：
--
作者：
Burkhart,SarahE;Llinas,RoxannaJ;Bartel,Bonnie
过氧化物酶体依靠过氧化物酶（PEX 蛋白）进行生物发生、输入膜和基质蛋白以及裂变。 PEX16 参与过氧化物酶体膜蛋白靶向并从内质网 (ER) 形成新生过氧化物酶体，在过氧化物酶中很不寻常，因为它共翻译插入 ER 并定位于 ER 和过氧化物酶体膜。人类、酵母和植物中的 PEX16 突变会导致一些常见的过氧化物酶体缺陷；然而，明显的功能差异阻碍了 PEX16 行动统一模型的开发。植物中唯一报道的 pex16 突变体拟南芥收缩种子 1 突变体是不可存活的，这使得胚胎发生后 PEX16 功能的分析变得复杂。在这里，我们鉴定了两个可行的拟南芥 pex16 等位基因，它们积累的 PEX16 蛋白水平可以忽略不计。两种突变体均表现出过氧化物酶体功能受损——储存油体的消耗减慢、基质蛋白的输入减少以及过氧化物酶体大小增加。此外，onepex16等位基因表现出生长减少（可以通过外部固定碳源缓解），对过氧化物酶体加工的激素前体的反应性降低，以及与其他pex突变体结合使过氧化物酶体功能恶化或改善。由于突变影响 PEX16 基因的不同区域，因此这些可行的 pex16 等位基因可以评估拟南芥 PEX16 及其功能域的重要性。
Peroxisomes rely on peroxins (PEX proteins) for biogenesis, importing membrane and matrix proteins, and fission. PEX16, which is implicated in peroxisomal membrane protein targeting and forming nascent peroxisomes from the endoplasmic reticulum (ER), is unusual among peroxins because it is inserted co‐translationally into the ER and localizes to both ER and peroxisomal membranes.PEX16mutations in humans, yeast, and plants confer some common peroxisomal defects; however, apparent functional differences have impeded the development of a unified model for PEX16 action. The only reportedpex16mutant in plants, theArabidopsis shrunken seed1mutant, is inviable, complicating analysis of PEX16 function after embryogenesis. Here, we characterized two viableArabidopsis pex16alleles that accumulate negligible PEX16 protein levels. Both mutants displayed impaired peroxisome function − slowed consumption of stored oil bodies, decreased import of matrix proteins, and increased peroxisome size. Moreover, onepex16allele exhibited reduced growth that could be alleviated by an external fixed carbon source, decreased responsiveness to peroxisomally processed hormone precursors, and worsened or improved peroxisome function in combination with otherpexmutants. Because the mutations impact different regions of thePEX16gene, these viablepex16alleles allow assessment of the importance ofArabidopsisPEX16 and its functional domains.