Functional analysis of Arabidopsis V-ATPase subunit VHA-E isoforms.
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.
Dettmer
Jan
J
ZMBP - Plant Physiology, Universität Tübingen, Auf der Morgenstelle 1, 72076 Tübingen, Germany.
Liu
Tzu-Yin
TY
Schumacher
Karin
K
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D007527:Isoenzymes / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D010802:Phylogeny; D030821:Plants, Genetically Modified; D021122:Protein Subunits / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D025262:Vacuolar Proton-Translocating ATPases / Q000145:classification / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D007527:Isoenzymes; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D025262:Vacuolar Proton-Translocating ATPases