Chemical. CAS 856243-80-6. Formula C19H18BrN3O. MW 384.3. WP1130 is a second-generation tyrphostin derivative initially identified as a JAK2 signaling inhibitor through JAK2 ubiquitination that reduces STAT activation stimulated by cytokines such as IL-6 and IL-3 through the rapid down-regulation of upstream JAK kinases. WP1130 has also been identified as a partially selective cell permeable deubiquitinating enzyme/deubiquitinase DUB inhibitor that directly inhibits DUB activity of USP9x, USP5, USP14, USP24, UCH37, UCHL1 and UCHL5, leading to rapid accumulation of polyubiquitinated K48/K63-linked proteins into juxtanuclear aggresomes and tumor cell apoptosis, accounting for its anti-cancer properties. Through this mechanism, WP1130 has been shown to downregulate the antiapoptotic proteins Bcr/Abl and Jak2 and to upregulate the proapoptotic proteins MCL-1 and p53.