Substrates and Regulation of the RNA Phosphatase DUSP11
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DUSP11 (Dual-specificity phosphatase 11) is an understudied human RNA phosphatase with an unclear function. DUSP11 converts 5′ triphosphates on RNAs into 5′ monophosphates, and it is required for the efficient biogenesis of some bovine leukemia virus-encoded microRNAs1. However, there is little understanding of DUSP11 substrates and the biochemical pathways it participates in. Here, I test the activity of DUSP11 on potential viral and transposon RNA substrates as well as the potential regulation of DUSP11 via its C terminus phosphorylation. My in vitro experiments show that DUSP11 can act on triphosphorylated viral and Alu RNAs and render them susceptible to XRN-1-mediated degradation. In contrast, knockout of the DUSP11 homolog PIR-1 in C. elegans did not lead to the accumulation of RNAs derived from the transposable element CELE45, implying possibly different functionality for the phosphatase in worms and mammals. My work also shows that mutations of individual phosphorylation sites of the DUSP11 C terminus do not substantially alter activity in a mammalian cell-based assay.