Pan Ronghui, Hu Jianping
MSU-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA.
Plant Biology Department, Michigan State University, East Lansing, MI, USA.
Commun Integr Biol. 2017 Jun 22;10(4):e1338991. doi: 10.1080/19420889.2017.1338991. eCollection 2017.
Peroxisomes, chloroplasts, and mitochondria are essential eukaryotic organelles that host a suite of metabolic processes crucial to energy metabolism and development. Regulatory mechanisms of the dynamics and biogenesis of these important organelles have begun to be discovered in plants. We recently showed that, aside from its previously reported role in targeting chloroplast protein import proteins, the Arabidopsis ubiquitin E3 ligase SP1 (suppressor of ppi1 locus1) negatively regulates peroxisome matrix protein import by promoting the ubiquitination and destabilization of PEX13 and possibly PEX14 and other components of the peroxisome protein import apparatus. Here, we compared protein sequence and domain structure of SP1-like proteins in Arabidopsis and their human homolog, Mitochondrial-Anchored Protein Ligase (MAPL). We further characterized SP1 protein in respect to its membrane topology and ubiquitin E3 ligase activity.
过氧化物酶体、叶绿体和线粒体是真核生物必不可少的细胞器，它们承载着一系列对能量代谢和发育至关重要的代谢过程。植物中这些重要细胞器的动态变化和生物发生的调控机制已开始被发现。我们最近发现，除了其先前报道的在靶向叶绿体蛋白输入蛋白方面的作用外，拟南芥泛素E3连接酶SP1（ppi1位点1的抑制因子）通过促进PEX13以及可能的PEX14和过氧化物酶体蛋白输入装置的其他成分的泛素化和不稳定化，对过氧化物酶体基质蛋白输入起负调控作用。在这里，我们比较了拟南芥中SP1样蛋白及其人类同源物线粒体锚定蛋白连接酶（MAPL）的蛋白质序列和结构域结构。我们进一步对SP1蛋白的膜拓扑结构和泛素E3连接酶活性进行了表征。
