New Cdc2 Tyr 4 phosphorylation by dsRNA-activated protein kinase triggers Cdc2 polyubiquitination and G2 arrest under genotoxic stresses.
Cell division cycle 2 (Cdc2) protein is an essential subunit of M-phase kinase (MPK), which has a key role in G2/M transition. Even though the control of MPK activity has been well established with regard to the phosphorylation of Cdc2 at Thr 14 and/or Tyr 15 and Thr 161, little is known about the proteolytic control of Cdc2. In this study, we observed that Cdc2 was downregulated under genotoxic stresses and that double-stranded RNA-activated protein kinase (PKR) was involved in the process. The PKR-mediated Tyr4 phosphorylation triggered Cdc2 ubiquitination. Phospho-mimic mutations at the Tyr 4 residue (Y4D or Y4E) caused significant ubiquitination of Cdc2 even in the absence of PKR. Our findings demonstrate that (i) PKR, Ser/Thr kinase, phosphorylates its new substrate Cdc2 at the Tyr 4 residue, (ii) PKR-mediated Tyr 4-phosphorylation facilitates Cdc2 ubiquitination and proteosomal degradation, (iii) unphosphorylated Tyr 4 prevents Cdc2 ubiquitination, and (iv) downstream from p53, PKR has a crucial role in G2 arrest and triggers Cdc2 downregulation under genotoxic conditions.
Yoon
Cheol-Hee
CH
Department of Biological Sciences, Sungkyunkwan University, Suwon, Gyeonggi-Do, South Korea.
Miah
Mohammad Alam
MA
Kim
Kwang Pyo
KP
Bae
Yong-Soo
YS
D016203:CDC2 Protein Kinase / Q000737:chemistry / Q000378:metabolism*; D004249:DNA Damage; D015536:Down-Regulation; D016195:G2 Phase; D045325:HCT116 Cells; D006801:Humans; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D025821:Polyubiquitin / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D054875:Ubiquitination; D019892:eIF-2 Kinase / Q000378:metabolism*
D025821:Polyubiquitin; D019000:Phosphotyrosine; D019892:eIF-2 Kinase; D016203:CDC2 Protein Kinase
Oncogene. 2001 Dec 6;20(56):8045-56
11781817
Proc Natl Acad Sci U S A. 2009 May 12;106(19):7852-7
19416861
EMBO J. 2009 Jul 22;28(14):2100-13
19536131
J Biol Chem. 2007 Oct 26;282(43):31675-87
17785458
J Biol Chem. 2008 Feb 8;283(6):3097-3108
18063576
Proc Natl Acad Sci U S A. 2006 Jan 3;103(1):63-8
16373505
J Cell Physiol. 2005 Oct;205(1):25-31
15880455
Oncogene. 2001 Apr 5;20(15):1803-15
11313928
FEBS Lett. 2007 Sep 4;581(22):4325-32
17716668
Cell. 1991 Oct 4;67(1):197-211
1913817
Nature. 1977 Aug 11;268(5620):540-2
196217
Science. 1995 Oct 6;270(5233):86-90
7569953
Cell. 2007 Jun 15;129(6):1125-40
17574025
Nature. 1988 Sep 15;335(6187):251-4
3412486
Proc Natl Acad Sci U S A. 2004 Mar 30;101(13):4419-24
15070733
J Biol Chem. 2006 Aug 25;281(34):24161-70
16807237