Phosphatase Superfamily RTR1

Phosphatase Classification: Fold RTR1: Superfamily 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 eukaryotes. It is absent from the 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 (RTR1, RTR2).

Domain Structure

RTR1 has a conserved phosphatase domain with a unique mechanism of action [1]. Yeast RTR1 has a C-terminal region (CTR) that auto-inhibits the catalytic domain [2]. The human homolog, RPAP2, has a longer tail with limited sequence similarity to CTR, and is known to bind RNA pol II subunit Rpb6 and to be involved in pre-mRNA 3'-end formation [3].

Function

Yeast RTR1 dephosphorylates serine-5 of CTD repeats of RNA pol II [4, 5]. These findings were challenged by later studies [6], but more recent study supports its activity towards serine-5 [2] and also the anti-termination tyrosine-1 on CTD repeats [2].

References

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