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The new study, published recently by the journal ACS Chemical Biology , describes new compounds that inhibit an important enzyme calledPRMT1 (protein arginine methyltransferase 1). The new inhibitorswill be useful to scientists who study PRMT1-related biologicalpathways in cells and who are developing drug treatments forPRMT1-related inflammatory conditions and cancers. Standard screening techniques had been unable to distinguishbetween compounds that inhibit PRMT1 and those that inhibit othercommon PRMT family enzymes. In the new study, scientists fromseveral Scripps Research laboratories collaborated to devise thefirst PRMT1-specific screening technique. "We were able totarget a screening probe to a specific amino acid found on PRMT1,but not on most other PRMT enzymes," said the study'sprincipal investigator Scripps Research Assistant Professor KerriA. Mowen. Mowen has been studying PRMT1 since her graduate school days, and,like others in the field, has been acutely aware of the need forselective PRMT1 inhibitors. The enzyme modifies the functionalityof proteins by attaching a methyl group to their arginine aminoacids; as such, it is involved in some of the most basic processesin cells. For example, Mowen and her colleagues showed in 2004 thatPRMT1 helps drive the production of the key immune-stimulatingproteins interferon-gamma and interleukin-4. But although PRMT1 was known to be responsible for nearly all thearginine methylation that goes in mammalian cells, no one had beenable to develop selective PRMT1 inhibitors, since the 10 other PRMTenzymes are nearly identical, structurally and biochemically. Eventhe removal of PRMT1's gene from lab mice as an alternative way tostudy its functions was problematic, since mouse embryos can'tsurvive without the protein. Inspiration Close By The inspiration for the new PRMT1-selective screening techniquecame from research performed in the neighboring laboratory ofco-author Benjamin F. Cravatt III, who chairs the Scripps ResearchDepartment of Chemical Physiology. As reported in 2010 in thejournal Nature , Cravatt and his team screened tens of thousands of human andmouse proteins for the presence of hyper-reactive cysteine aminoacids, which almost certainly mark functional sites on thoseproteins. PRMT1 was found to be one of thereactive-cysteine-containing proteins -- and all but one other,comparatively rare PRMT enzyme was known to lack that cysteine. "We took that discovery a step further, and we were able tofind a probe that specifically would recognize that cysteine inPRMT1," said Mowen, who was one of Cravatt's collaborators onthe 2010 study. She and her colleagues first verified that the reactive cysteine inPRMT1 is in the active site of the enzyme. They then found afluorescent probe that would bind to that cysteine. If a testcompound acted as an inhibitor by fastening to PRMT1's active site,it should interfere with the probe's binding, and the probe'sfluorescence-based signal therefore should be lower. By contrast,if a test compound failed to bind to PRMT1's active site, the probeshould bind normally and its signal should remain elevated. "We were able to verify, using available non-specificinhibitors of PRMT enzymes, that they did indeed bind to PRMT1 andprevent the probe from binding, and that was the proof-of-conceptthat enabled us to go ahead with a screen," said Myles B. C.Dillon, a graduate student in Mowen's lab who was lead author ofthe study. Exploring Libraries of Potential Dillon and Mowen turned to collaborator Scripps Research ProfessorHugh Rosen, curator of a library of 16,000 chemical compounds knownas the Maybridge Hitfinder Collection. By applying these compounds,one by one, along with the probe molecule, to solutions of PRMT1,the team was able to determine the compounds' abilities to bindPRMT1's active site and thus act as inhibitors. Importantly, thesetup was simple enough to be adapted, with Rosen's help, as anautomated, "high-throughput" technique, capable ofscreening thousands of compounds. In this way, the scientists were able to sift through the compoundlibrary to find two candidate PRMT1-selective inhibitors."They have good efficacy and specificity, and we might be ableto modify them to make them even better," said Dillon. Mowen, Dillon, and their colleagues now have a National Institutesof Health (NIH) grant to use their screening technique with a300,000-compound NIH library, also curated at Scripps Research."Once we get the results from this larger screen, we'llconsider our best inhibitor compounds and decide which ones tostart optimizing," said Dillon. To Mowen, the success of the project owes much to the collaborativespirit at Scripps Research. "Many labs here are developingcutting-edge technologies that empower other labs' work, andcertainly we were able to benefit from that," she said."It's a very supportive, synergistic environment.". The e-commerce company in China offers quality products such as China LED Module , Dual Color LED Display Manufacturer, and more. For more , please visit Rental LED Display today!
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