Phosphatase Fold RTR1

Phosphatase Classification: Fold RTR1

RTR1 is a phosphatase conserved in eukaryotes that regulates the phosphorylation states of C-terminal domain (CTD) of RNA polymerase II.

Evolution

RTR1 is found in most of eukaryotes. It is absent from Monosiga and sponge genome, though it is perhaps due to the quality of genome assembly. It is single copy in human, sea urchin, fruit fly, C elegans. However, two copies are found in yeast.

Domain

RTR1 has a conserved domain that carries out the phosphatase activity. Yeast RTR1 has a C-terminal region (CTR) that auto-inhibits the catalytic domain [1]. Human RTR1 encoded by gene RPAP2 has a longer tail, but whether its function is unclear given the limited sequence similarity with CTR in yeast RTR1.

Function

Yeast RTR1 encodes the phosphatase that dephosphorylates serine-5 of CTD repeats of RNA pol II [2, 3]. These findings were challenged by later studies [4], but more recent study supports its activity towards serine-5 [1]. Moreover, it has been shown that Rtr1 dephosphorylates not only serine-5 but also the newly described anti-termination tyrosine 1 marker on CTD repeats [1].

References

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