Chemical Tools To Decipher Regulation of Phosphatases by Proline Isomerization on Eukaryotic RNA Polymerase II.
Proline isomerization greatly impacts biological signaling but is subtle and difficult to detect in proteins. We characterize this poorly understood regulatory mechanism for RNA polymerase II carboxyl terminal domain (CTD) phosphorylation state using novel, direct, and quantitative chemical tools. We determine the proline isomeric preference of three CTD phosphatases: Ssu72 as cis-proline specific, Scp1 and Fcp1 as strongly trans-preferred. Due to this inherent characteristic, these phosphatases respond differently to enzymes that catalyze the isomerization of proline, like Ess1/Pin1. We demonstrate that this selective regulation of RNA polymerase II phosphorylation state exists within human cells, consistent with in vitro assays. These results support a model in which, instead of a global enhancement of downstream enzymatic activities, proline isomerases selectively boost the activity of a subset of CTD regulatory factors specific for cis-proline. This leads to diversified phosphorylation states of CTD in vitro and in cells. We provide the chemical tools to investigate proline isomerization and its ability to selectively enhance signaling in transcription and other biological contexts.
Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin , Austin, Texas 78712, United States.
Joshua E
JE
Mayfield
Department of Chemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.
Shuang
S
Fan
1 Cancer Research Institute, Beth Israel Deaconess Cancer Center, Harvard Medical School , Boston, Massachusetts 02215, United States.|Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston, Massachusetts 02215, United States.
Shuo
S
Wei
Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin , Austin, Texas 78712, United States.
Mengmeng
M
Zhang
Department of Molecular Biology, UT Southwestern Medical Center , 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States.
Bing
B
Li
Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin , Austin, Texas 78712, United States.
Andrew D
AD
Ellington
Department of Chemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.
Felicia A
FA
Etzkorn
Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin , Austin, Texas 78712, United States.
Yan Jessie
YJ
Zhang
D000818:Animals; D015153:Blotting, Western; D018360:Crystallography, X-Ray; D004330:Drosophila / Q000201:enzymology; D004789:Enzyme Activation / Q000502:physiology; D006801:Humans; D007536:Isomerism; D008954:Models, Biological; D015394:Molecular Structure; D010749:Phosphoprotein Phosphatases / Q000737:chemistry* / Q000378:metabolism*; D011392:Proline / Q000737:chemistry*; D012319:RNA Polymerase II / Q000737:chemistry* / Q000378:metabolism*
D011392:Proline; D012319:RNA Polymerase II; D010749:Phosphoprotein Phosphatases