Korneenko Tatyana V, Pestov Nikolay B, Ahmad Nisar, Okkelman Irina A, Dmitriev Ruslan I, Shakhparonov Mikhail I, Modyanov Nikolai N
Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117871, Russia.
Department of Physiology and Pharmacology and Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, 3000 Arlington Ave, Toledo, OH 43614, USA.
Sci Rep. 2016 Mar 4;6:22395. doi: 10.1038/srep22395.
ATP1B4 genes represent a rare instance of orthologous vertebrate gene co-option that radically changed properties of the encoded BetaM proteins, which function as Na,K-ATPase subunits in lower vertebrates and birds. Eutherian BetaM has lost its ancestral function and became a muscle-specific resident of the inner nuclear membrane. Our earlier work implicated BetaM in regulation of gene expression through direct interaction with the transcriptional co-regulator SKIP. To gain insight into evolution of BetaM interactome we performed expanded screening of eutherian and avian cDNA libraries using yeast-two-hybrid and split-ubiquitin systems. The inventory of identified BetaM interactors includes lamina-associated protein LAP-1, myocyte nuclear envelope protein Syne1, BetaM itself, heme oxidases HMOX1 and HMOX2; transcription factor LZIP/CREB3, ERGIC3, PHF3, reticulocalbin-3, and β-sarcoglycan. No new interactions were found for chicken BetaM and human Na,K-ATPase β1, β2 and β3 isoforms, indicating the uniqueness of eutherian BetaM interactome. Analysis of truncated forms of BetaM indicates that residues 72-98 adjacent to the membrane in nucleoplasmic domain are important for the interaction with SKIP. These findings demonstrate that evolutionary alterations in structural and functional properties of eutherian BetaM proteins are associated with the increase in its interactome complexity.
ATP1B4基因代表了脊椎动物直系同源基因共选择的一个罕见例子，这种共选择彻底改变了所编码的βM蛋白的特性，βM蛋白在低等脊椎动物和鸟类中作为钠钾ATP酶亚基发挥作用。真兽亚纲动物的βM已经失去了其祖先功能，成为内核膜的肌肉特异性驻留蛋白。我们早期的研究表明，βM通过与转录共调节因子SKIP直接相互作用参与基因表达的调控。为了深入了解βM相互作用组的进化，我们使用酵母双杂交和分裂泛素系统对真兽亚纲动物和鸟类的cDNA文库进行了扩展筛选。已鉴定的βM相互作用蛋白包括核纤层相关蛋白LAP-1、心肌细胞核膜蛋白Syne1、βM自身、血红素氧化酶HMOX1和HMOX2；转录因子LZIP/CREB3、ERGIC3、PHF3、网钙蛋白-3和β-肌聚糖。未发现鸡βM与人钠钾ATP酶β1、β2和β3亚型有新的相互作用，这表明真兽亚纲动物βM相互作用组具有独特性。对βM截短形式的分析表明，核质结构域中与膜相邻的72-98位残基对于与SKIP的相互作用很重要。这些发现表明，真兽亚纲动物βM蛋白结构和功能特性的进化改变与其相互作用组复杂性的增加有关。
