Disease relevance of Ance

• We report the isolation and characterization of a putative angiotensin converting enzyme (ACE) in Drosophila, called Race. General interest in mammalian ACE stems from its association with high blood pressure; ACE has also been implicated in a variety of other physiological processes including the processing of neuropeptides and gut peristalsis [1].

High impact information on Ance

• In addition, we demonstrate that ectopically expressed Zen can activate targets like Race in the presence of low level Smads, indicating that the role of the highest activity of the BMP gradient is to activate zen [2].
• A 533 bp enhancer from the Race promoter region is shown to mediate selective expression in the amnioserosa, as well as the anterior and posterior midgut rudiments [3].
• We show that the Smad transcription factors, which are intracellular transducers of Dpp signaling, are essential activators of Race in vivo [4].
• Furthermore, increasing the affinity of the Smad binding sites in the Race enhancer broadens the expression pattern of a linked reporter gene and alters its behavior in mutant embryos to that characteristic of a distinct threshold response [4].
• An essential role in molting and morphogenesis of Caenorhabditis elegans for ACN-1, a novel member of the angiotensin-converting enzyme family that lacks a metallopeptidase active site [5].

Biological context of Ance

• DTK-5 was the best substrate of this family, but the apparent high K(m) for hydrolysis by Ance suggested that this peptide would not be a natural Ance substrate [6].
• Peptidyl dipeptidases (Ance and Acer) of Drosophila melanogaster: major differences in the substrate specificity of two homologs of human angiotensin I-converting enzyme [6].
• Taken together, the expression pattern and mutant phenotype suggest that Ance is required for spermatid differentiation, probably through the processing of a regulatory peptide synthesised within the developing cyst [7].
• We propose that the expression of Ance in imaginal cells is co-ordinated by exposure to ecdysteroid (moulting hormone) during the last larval instar moult to increase levels of ACE-like activity during metamorphosis [8].
• One of these (Acer) is expressed in the embryonic heart, whereas the second enzyme (Ance) is expressed in several tissues at different stages of the life cycle [9].

Anatomical context of Ance

• This low affinity for DTK-5 is the likely reason why the peptide was not rapidly degraded in D. melanogaster hemolymph, where Ance was shown to be a major peptide-degrading activity [6].
• The failure of Ance mutant testes to form individualisation complexes may be due to a failure in correct spermatid differentiation [7].
• Ance mRNA is found mainly in large primary spermatocytes and is not detectable in cyst cells [7].
• Testes lacking germ cells have reduced levels of ACE activity, and no Ance protein is detectable by immunocytochemistry, indicating that the germ cells are the major site of Ance synthesis [7].
• This increase was attributed to the induction of Ance expression during the wandering phase of the last larval instar in the imaginal cells (imaginal discs, abdominal histoblasts, gut imaginal cells and imaginal salivary gland) [8].

Associations of Ance with chemical compounds

• Physiological levels of 20-hydroxyecdysone induced the synthesis of ACE-like activity and Ance protein by a wing disc cell line (Cl.8+), confirming that Ance is an ecdysteroid-responsive gene [8].
• Furthermore, Acer did not hydrolyse the synthetic substrates Phe-Ser-Pro-Arg-Leu-Gly-Arg-Arg and Phe-Ser-Pro-Arg-Leu-Gly-Lys-Arg, two partially processed putative locustamyotropin precursors, under conditions where Ance produced 82% substrate hydrolysis [10].
• Complete inhibition of the endopeptidic hydrolysis of the LomTK-1 by a disc homogenate required a combination of captopril and the neprilysin inhibitor, phosphoramidon, providing biochemical evidence for a neprilysin-like peptidase, in addition to Ance, in imaginal discs of D. melanogaster [11].
• When expressed in COS-7 cells, the AnCE protein is a secreted enzyme, which converts angiotensin I to angiotensin II and is inhibited by captopril (IC50 = 5.6 x 10(-9) M) and trandolaprilat (IC50 = 2 x 10(-8) M) [12].
• Two catalytic criteria demonstrate the functional resemblance of AnCE with the human ACE C domain: first, the kcat/Km of AcSDKP hydrolysis and secondly, the kcat/Km and optimal chloride concentration for hippuryl-His-Leu hydrolysis [13].

Other interactions of Ance

• Ance was generally much better than Acer at hydrolyzing peptides of 5-13 amino acids in length [6].
• However, in comparison, the D. melanogaster tachykinins, DTK-1, DTK-2, DTK-3 and DTK-4 were poor Ance substrates [6].
• Ance protein and mRNA were not detected in imaginal discs from wandering larvae of flies homozygous for the ecd ( 1 ) allele, a temperature-sensitive ecdysone-less mutant, suggesting that Ance expression is ecdysteroid-dependent [8].
• We present evidence that zen directly activates the amnioserosa-specific expression of a downstream target gene, Race (Related to angiotensin converting enzyme) [3].
• P-transformation assays and genetic complementation tests suggest that Race corresponds to a previously characterized lethal complementation group, 1(2)34Eb [1].

Analytical, diagnostic and therapeutic context of Ance

• We have investigated the relationship of Ance and Acer to the N- and C-domains of human sACE by genomic sequence analysis and by using domain-selective inhibitors, including RXP 407, a selective inhibitor of the human N-domain [14].
• Angiotensin-converting enzyme (ACE)-like enzyme activity was detected, by reverse-phase HPLC using the synthetic tripeptide Hip-His-Leu as a substrate [15].

References