Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Vuelta de Obligado 2490 2º, Buenos Aires, C1428ADN, Argentina.
Planta. 2011 Apr;233(4):661-74. doi: 10.1007/s00425-010-1329-0. Epub 2010 Dec 14.
Plasma membrane proton pumps (PM H(+)-ATPases) are involved in several physiological processes, such as growth and development, and abiotic stress responses. The major regulators of the PM H(+)-ATPases are proteins of the 14-3-3 family, which stimulate its activity. In addition, a novel interaction partner of the AHA1 PM H(+)-ATPase, named PPI1 (proton pump interactor, isoform 1), was identified in Arabidopsis thaliana. This protein stimulates the activity of the proton pump in vitro. In this work, we report the characterization of an A. thaliana PPI1 homolog in potato (Solanum tuberosum L.) named StPPI1. The full-length coding sequence of StPPI1 was obtained. The open reading frame (ORF) encodes a protein of 629 amino acids showing 50% identity with A. thaliana PPI1 protein. The StPPI1 ORF is divided into seven exons split by six introns. Southern blot analysis suggests that StPPI1 belongs to a family of related genes. Recombinant StPPI1 stimulates H(+)-ATPase activity in vitro. Basal levels of StPPI1 transcripts are observed in all tissues, however, StPPI1 expression is higher in proliferative regions (shoot apex and flower buds), flowers and leaves than in shoots and roots. StPPI1 mRNA levels significantly increase during tuber development. StPPI1 is induced by salt stress and cold. Drought and mechanical wounding slightly increase StPPI1 transcript levels. In addition, the expression of SlPPI1, the tomato homolog of StPPI1, was determined under adverse environmental conditions in tomato plants. SlPPI1 mRNA levels are increased by drought and cold, but are unaffected by salt stress. Mechanical wounding slightly increases SlPPI1 expression.
质膜质子泵（PM H（+）-ATPases）参与多种生理过程，如生长发育和非生物胁迫反应。PM H（+）-ATPases 的主要调节剂是 14-3-3 家族的蛋白质，它刺激其活性。此外，在拟南芥中鉴定出 AHA1 PM H（+）-ATPase 的一种新的相互作用伙伴，命名为 PPI1（质子泵相互作用蛋白，同工型 1）。该蛋白在体外刺激质子泵的活性。在这项工作中，我们报道了马铃薯（Solanum tuberosum L.）中 A. thaliana PPI1 同源物的特征，命名为 StPPI1。获得了 StPPI1 的全长编码序列。开放阅读框（ORF）编码 629 个氨基酸的蛋白质，与 A. thaliana PPI1 蛋白具有 50%的同一性。StPPI1 ORF 分为七个外显子，由六个内含子分隔。Southern blot 分析表明，StPPI1 属于相关基因家族。重组 StPPI1 体外刺激 H（+）-ATPase 活性。在所有组织中均观察到 StPPI1 转录本的基础水平，但在增殖区（芽尖和花蕾）、花和叶中的表达高于芽和根。StPPI1 mRNA 水平在块茎发育过程中显著增加。StPPI1 受盐胁迫和冷胁迫诱导。干旱和机械损伤略微增加 StPPI1 转录水平。此外，还确定了番茄同源物 SlPPI1 在番茄植物逆境条件下的表达。干旱和冷胁迫增加 SlPPI1 mRNA 水平，但盐胁迫对其无影响。机械损伤略微增加 SlPPI1 的表达。
