RNA polymerase II associated protein 2 (RPAP2)

RNA polymerase II associated protein 2 (RPAP2) is a protein phosphatase and transcription regulatory factor that binds to and regulates RNA polymerase II, the central enzyme responsible for mRNA synthesis in eukaryotes[1][2][4][7]. RPAP2 primarily functions by dephosphorylating serine residues (notably Ser-5) in the C-terminal domain (CTD) of Pol II, thus promoting or fine-tuning transcription initiation and elongation, especially of small nuclear RNA (snRNA) genes[2][7]. It recognizes phosphorylated Ser-7 of the CTD, influencing both transcriptional activity and RNA processing[2]. Structurally, RPAP2 binds between the jaw domains of the Pol II subunits RPB1 and RPB5, and is involved in nuclear import of RNA polymerase II[1]. RPAP2 is displaced from Pol II during the formation of the transcription pre-initiation complex and upon DNA engagement, consistent with its role in regulating Pol II assembly and nuclear transport rather than ongoing transcription[1][3]. In addition to its role in transcription, RPAP2 participates in the unfolded protein response by dephosphorylating ER stress sensors, with implications for cell fate under ER stress conditions[2]. The yeast homolog of RPAP2, Rtr1, shares similar functions but varies in phosphatase activity depending on the species[1]. As of now, RPAP2 is not a recognized therapeutic target, and no drugs are known to act directly on it. There are no reports of RPAP2 serving as a clinically actionable biomarker or significant safety concerns associated with its manipulation[2][4][7].

Other names

RPAP2C1orf82Rtr1FLJ13150Putative RNA polymerase II subunit B1 CTD phosphatase RPAP2RNA polymerase II-associated protein 2