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Peterson Jeffrey R , Lebensohn Andres M , Pelish Henry E , Kirschner Marc W
Biochemical Suppression of Small-Molecule Inhibitors: A Strategy to Identify Inhibitor Targets and Signaling Pathway Components
Chemistry & Biology (Cambridge, MA, United States). 2006 ;13(4) :443-452
PMID: AN 2006:390371   
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Summary: Identification of small-mol. targets remains an important challenge for chem. genetics. We report an approach for target identification and protein discovery based on functional suppression of chem. inhibition in vitro. We discovered pirl1, an inhibitor of actin assembly, in a screen conducted with cytoplasmic exts. Pirl1 was used to partially inhibit actin assembly in the same assay, and concd. biochem. fractions of cytoplasmic exts. were added to find activities that suppressed pirl1 inhibition. Two activities were detected, sep. purified, and identified as Arp2/3 complex and Cdc42/RhoGDI complex, both known regulators of actin assembly. We show that pirl1 directly inhibits activation of Cdc42/RhoGDI, but that Arp2/3 complex represents a downstream suppressor. This work introduces a general method for using low-micromolar chem. inhibitors to identify both inhibitor targets and other components of a signaling pathway. [on SciFinder (R)]
9 Biochemical Methods Division of Basic Sciences,Fox Chase Cancer Center, 333 Cottman Avenue,Philadelphia,PA,USA. Journal 1074-5521 written in English.