3. Noble MEM, Endicott JA, Johnson LN (2004) Protein kinase inhibitors: Insights into drug design from structure. Science 303: 1800–1805. 4. Davies SP, Reddy H, Caivano M, Cohen P (2000) Specificity and mechanism of action of some commonly used protein kinase inhibitors. Biochemical Journal 351: 95–105. 5. Bishop AC, Ubersax JA, Petsch DT, Matheos DP, Gray NS, et al. (2000) A chemical switch for inhibitor-sensitive alleles of any protein kinase. Nature 407: 395–401. 6. Knight ZA, Shokat KM (2007) Chemical Genetics: Where Genetics and Pharmacology Meet. Cell 128: 425–430. 7. Kim S, Shah K (2007) Dissecting yeast Hog1 MAP kinase pathway using a chemical genetic approach. Febs Letters 581: 1209–1216. 8. Macia J, Regot S, Peeters T, Conde N, Sole R, et al. (2009) Dynamic Signaling in the Hog1 MAPK Pathway Relies on High Basal Signal Transduction. Science Signaling 2: ra13. 9. Westfall PJ, Thorner J (2006) Analysis of mitogen-activated protein kinase signaling specificity in response to hyperosmotic stress: Use of an analog-sensitive HOG1 allele. Eukaryotic Cell 5: 1215–1228. 10. de Nadal E, Posas F (2010) Multilayered control of gene expression by stress- activated protein kinases. Embo Journal 29: 4–13. 11. Hohmann S (2002) Osmotic stress signaling and osmoadaptation in Yeasts. Microbiology and Molecular Biology Reviews 66: 300–372. 12. Hohmann S (2009) Control of high osmolarity signalling in the yeast Saccharomyces cerevisiae. Febs Letters 583: 4025–4029. 13. Westfall PJ, Patterson JC, Chen RE, Thorner J (2008) Stress resistance and signal fidelity independent of nuclear MAPK function. Proceedings of the National Academy of Sciences of the United States of America 105: 12212–12217. 14. Thorsen M, Di Y, Tangemo C, Morillas M, Ahmadpour D, et al. (2006) The MAPK Hog1p modulates Fps1p-dependent arsenite uptake and tolerance in yeast. Molecular Biology of the Cell 17: 4400–4410. 15. Proft M, Struhl K (2004) MAP kinase-mediated stress relief that precedes and regulates the timing of transcriptional induction. Cell 118: 351–361. 16. Bilsland-Marchesan E, Arino J, Saito H, Sunnerhagen P, Posas F (2000) Rck2 kinase is a substrate for the osmotic stress-activated mitogen-activated protein kinase Hog1. Molecular Biology of the Cell 20: 3887–3895. 17. Clotet J, Escote X, Adrover MA, Yaakov G, Gari E, et al. (2006) Phosphorylation of Hsl1 by Hog1 leads to a G(2) arrest essential for cell survival at high osmolarity. Embo Journal 25: 2338–2346. 18. Escote X, Zapater M, Clotet J, Posas F (2004) Hog1 mediates cell-cycle arrest in G1 phase by the dual targeting of Sic1. Nature Cell Biology 6: 997–1002. 19. Yaakov G, Duch A, Garcia-Rubio M, Clotet J, Jimenez J, et al. (2009) The Stress-activated Protein Kinase Hog1 Mediates S Phase Delay in Response to Osmostress. Molecular Biology of the Cell 20: 3572–3582. 20. Migdal I, Ilina Y, Tama´s MJ, Wysocki R (2008) Mitogen-activated protein kinase Hog1 mediates adaptation to G1 checkpoint arrest during arsenite and hyperosmotic stress. Eukaryotic Cell 7: 1309–1317. 21. Goldstein DM, Kuglstatter A, Lou Y, Soth MJ (2009) Selective p38a Inhibitors Clinically Evaluated for the Treatment of Chronic Inflammatory Disorders. Journal of Medicinal Chemistry 53: 2345–2353. 22. Cuenda A, Rousseau S (2007) p38 MAP-kinases pathway regulation, function and role in human diseases. Biochim Biophys Acta 1773: 1358–1375. 23. Kim JY, Choi JA, Kim TH, Yoo YD, Kim JI, et al. (2002) Involvement of p38 mitogen-activated protein kinase in the cell growth inhibition by sodium arsenite. Journal of Cellular Physiology 190: 29–37. 24. Li JP, Yang JL (2007) Cyclin B1 proteolysis via p38 MAPK signaling participates in G2 checkpoint elicited by arsenite. Journal of Cellular Physiology 212: 481–488. 25. Cuenda A, Rouse J, Doza YN, Meier R, Cohen P, et al. (1995) Sb-203580 Is a Specific Inhibitor of a Map Kinase Homolog Which Is Stimulated by Cellular Stresses and Interleukin-1. Febs Letters 364: 229–233. A Hog1 Inhibitor for Analyzing Kinase Signaling 26. Young PR, McLaughlin MM, Kumar S, Kassis S, Doyle ML, et al. (1997) Pyridinyl imidazole inhibitors of p38 mitogen-activated protein kinase bind in the ATP site. Journal of Biological Chemistry 272: 12116–12121. 27. Dine´r P, Andersson T, Kjellen J, Elbing K, Hohmann S, et al. (2009) Short cut to 1,2,3-triazole-based p38 MAP kinase inhibitors via [3+2]-cycloaddition chemistry. New Journal of Chemistry 33: 1010–1016. 28. Schro¨dinger (2008) Glide [5.0]. New York: Schro¨dinger, LLC. 29. Schro¨dinger (2008) Macromodel [9.0]. New York: Schro¨dinger, LLC. 30. Jackson JR, Bolognese B, Hillegass L, Kassis S, Adams J, et al. (1998) Pharmacological effects of SB 220025, a selective inhibitor of P38 mitogen- activated protein kinase, in angiogenesis and chronic inflammatory disease models. Journal of Pharmacology and Experimental Therapeutics 284: 687–692. 31. Wolfe JP, Tomori H, Sadighi JP, Yin JJ, Buchwald SL (2000) Simple, efficient catalyst system for the palladium-catalyzed amination of aryl chlorides, bromides, and triflates. Journal of Organic Chemistry 65: 1158–1174. 32. Krantz M, Ahmadpour D, Ottosson LG, Warringer J, Waltermann C, et al. (2009) Robustness and fragility in the yeast high osmolarity glycerol (HOG) signal-transduction pathway. Molecular Systems Biology 5: 281. 33. Maeda T, Wurgler-Murphy SM, Saito H (1994) A two-component system that regulates an osmosensing MAP kinase cascade in yeast. Nature 369: 242–245. 34. Balzi E, Wang M, Leterme S, Vandyck L, Goffeau A (1994) Pdr5, a Novel Yeast Multidrug-Resistance Conferring Transporter Controlled by the Transcription Regulator Pdr1. Journal of Biological Chemistry 269: 2206–2214. 35. Wurgler-Murphy SM, Maeda T, Witten EA, Saito H (1997) Regulation of the Saccharomyces cerevisiae HOG1 mitogen-activated protein kinase by the PTP2 and PTP3 protein tyrosine phosphatases. Molecular Cell Biology 17: 1289–1297. 36. Rep M, Krantz M, Thevelein JM, Hohmann S (2000) The Transcriptional Response of Saccharomyces cerevisiae to Osmotic Shock. Journal of Biological Chemistry 275: 8290–8300. 37. Rudolf F, Pelet S, Peter M (2008) Regulation of MAPK Signaling in Yeast; Posas F, Nebrada AR, eds. Springer Berlin / Heidelberg, pp 187–204. 38. O’Rourke SM, Herskowitz I (1998) The Hog1 MAPK prevents cross talk between the HOG and pheromone response MAPK pathways in Saccharomy- ces cerevisiae. Genes & Development 12: 2874–2886. 39. Costanzo M, Baryshnikova A, Bellay J, Kim Y, Spear ED, et al. (2010) The genetic landscape of a cell. Science 327: 425–431. 40. Tong AH, Lesage G, Bader GD, Ding H, Xu H, et al. (2004) Global mapping of the yeast genetic interaction network. Science 303: 808–813. 41. Reiser V, Ruis H, Ammerer G (1999) Kinase Activity-dependent Nuclear Export Opposes Stress-induced Nuclear Accumulation and Retention of Hog1 Mitogen-activated Protein Kinase in the Budding Yeast Saccharomyces cerevisiae. Molecular and Cellular Biology 10: 1147–1161. 42. Warringer J, Blomberg A (2003) Automated screening in environmental arrays allows analysis of quantitative phenotypic profiles in Saccharomyces cerevisiae. Yeast 20: 53–67. 43. Amberg D, Burke D, Strathern J (2005) Methods in Yeast Genetics: A Cold Spring Harbor Laboratory Course Manual. New York: Cold Spring Harbor Laboratory Press. 44. de Nadal E, Casadome L, Posas F (2003) Targeting the MEF2-Like Transcription Factor Smp1 by the Stress-Activated Hog1 Mitogen-Activated Protein Kinase. Molecular and Cellular Biology 23: 229–237. 45. Hutti JE, Jarrell ET, Chang JD, Abbott DW, Storz P, et al. (2004) A rapid method for determining protein kinase phosphorylation specificity. Nature Methods 1: 27–29. 46. Ericson E, Gebbia M, Heisler LE, Wildenhain J, Tyers M, et al. (2008) Off- target effects of psychoactive drugs revealed by genome-wide assays in yeast. PLoS Genetics 4: e1000151. 47. Pierce SE, Davis RW, Nislow C, Giaever G (2007) Genome-wide analysis of barcoded Saccharomyces cerevisiae gene-deletion mutants in pooled cultures. Nature Protocols 2: 2958–2974. PLoS ONE | www.plosone.org 11 May 2011 | Volume 6 | Issue 5 | e20012