Protein phosphatase 1 dephosphorylates Orc2.

Kyung Yong Lee, June Sung Bae, Gwang Su Kim, Deog Su Hwang

Biochemical and biophysical research communications 2014 May 9

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Phosphorylation of Thr(116) and Thr(226) on Orc2, one of the six subunits of the origin recognition complex (ORC), by cyclin A/CDK2 during S phase leads to the dissociation of Orc2, Orc3, Orc4, and Orc5 subunits (Orc2-5) from human chromatin and replication origins. The phosphorylated Orc2 becomes dephosphorylated in the late M phase of the cell cycle. Here we show that protein phosphatase 1 (PP1) dephosphorylates Orc2. Dephosphorylation of Orc2 was accompanied by associating the dissociated Orc subunits with chromatin. Inhibitors of PP1 preferentially inhibited the dephosphorylation of Orc2. The overexpression of the α, β and γ PP1 isoforms decreased the amount of phosphorylated Orc2, and the depletion of these isoforms by RNA interference increased the amount of phosphorylated Orc2. These results suggest that PP1 dephosphorylates Orc2 to promote the binding of ORC to chromatin. Copyright © 2014 Elsevier Inc. All rights reserved.

Citation

Kyung Yong Lee, June Sung Bae, Gwang Su Kim, Deog Su Hwang. Protein phosphatase 1 dephosphorylates Orc2. Biochemical and biophysical research communications. 2014 May 9;447(3):437-40