ZMBP - Plant Physiology, Universität Tübingen, Auf der Morgenstelle 1, 72076 Tübingen, Germany.
Eur J Cell Biol. 2010 Feb-Mar;89(2-3):152-6. doi: 10.1016/j.ejcb.2009.11.008. Epub 2009 Nov 28.
Acidification of endomembrane compartments by the vacuolar H(+)-ATPase (V-ATPase) is an important mechanism to generate microenvironments suitable for various cellular functions. Differential assembly of subunit isoforms provides the potential to flexibly adapt the proton-pumping V-ATPase complex to changing physiological conditions and cell type-specific requirements. In Arabidopsis, the regulatory V-ATPase subunit E (VHA-E) is encoded by three genes with distinct expression patterns. We show here that VHA-E2, which belongs to a clade of pollen-specific VHA-E isoforms present in all higher plants, has a specialized but non-essential function during gametophyte development. Similarly, loss of the epidermis-specific isoform VHA-E3, which we show here to be transcriptionally regulated by the phytohormone jasmonic acid, does not cause obvious phenotypic changes. Furthermore, when expressed ubiquitously, VHA-E3, in contrast to VHA-E2, is able to complement loss of the essential subunit VHA-E1 indicating different degrees of functional specialization among the Arabidopsis VHA-E isoforms.
液泡 H(+)-ATP 酶（V-ATPase）对内质网隔室的酸化是生成适合各种细胞功能的微环境的重要机制。亚基同工型的差异组装为灵活适应不断变化的生理条件和细胞类型特异性需求的质子泵 V-ATPase 复合物提供了潜力。在拟南芥中，调节性 V-ATPase 亚基 E（VHA-E）由三个具有不同表达模式的基因编码。我们在这里表明，属于所有高等植物花粉特异性 VHA-E 同工型的一个分支的 VHA-E2 在配子体发育过程中具有特殊但非必需的功能。类似地，表皮特异性同工型 VHA-E3 的缺失，我们在这里表明它受植物激素茉莉酸的转录调控，不会引起明显的表型变化。此外，当在泛表达时，VHA-E3 与 VHA-E2 相反，能够弥补必需亚基 VHA-E1 的缺失，表明拟南芥 VHA-E 同工型之间存在不同程度的功能专业化。
