High impact information on Vha44

• As the ultimate target is the V-ATPase in the apical plasma membrane, this selective activation of mitochondria is clearly adaptive [1].
• The results highlight the dynamic nature and both spatial and temporal heterogeneity of calcium signaling possible in differentiated, organotypic cells and provide a new model for neuroendocrine control of V-ATPase [1].
• Lethality of these alleles could be reverted by transformation of flies with a wild type vha55::GFP fusion, confirming that the lethal phenotype described for these alleles was due to defects in V-ATPase function [2].
• One enhancer trap revealed expression of the gene encoding the C subunit of vacuolar ATPase (V-ATPase) in the medial cells of the ring gland, which produce the juvenile hormone that controls progression through developmental stages [3].
• The multifunctional Drosophila melanogaster V-ATPase is encoded by a multigene family [4].

Biological context of Vha44

• Involvement of V-ATPase in the regulation of cell size in the fly's visual system [5].
• Genome-wide survey of V-ATPase genes in Drosophila reveals a conserved renal phenotype for lethal alleles [6].
• The vacuolar H+-ATPase (V-ATPase) is a multisubunit enzyme that couples ATP hydrolysis to proton pumping across membranes [7].

Anatomical context of Vha44

• Moreover, vacuolar-type H+-ATPase (V-ATPase) in the optic lobe is thought also to participate in such regulation [5].
• In the visual systems of both fly species V-ATPase was localized immunocytochemically to the compound eye photoreceptors [5].
• For each subunit, the single gene identified previously by microarray, as upregulated and abundant in tubules, is shown to be similarly abundant in other epithelia in which V-ATPases are known to be important; there thus appears to be a single dominant "plasma membrane" V-ATPase holoenzyme in Drosophila [6].
• Intracellular pH regulation by the plasma membrane V-ATPase in Malpighian tubules of Drosophila larvae [8].

Associations of Vha44 with chemical compounds

• The transparent Malpighian tubule phenotype first identified in lethal alleles of vha55, the gene encoding the B-subunit, is shown to be general to those plasma membrane V-ATPase subunits for which lethal alleles are available, and to be caused by failure to accumulate uric acid crystals [6].

Analytical, diagnostic and therapeutic context of Vha44

• Site-directed mutagenesis was used to create two distinct, catalytically impaired C subunit mutants of the human and Arabidopsis genes [9].

References