Geletu Heye, Mulu (2006): Proteomic analysis of acute promyelocytic leukemia: PML-RARapha promotes mitotic exit by increased expression and decreased phosphorylation of OP18 at serine 63. Dissertation, LMU München: Faculty of Medicine |
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Abstract
We applied mass spectrometry based approach to explore the proteins differentially regulated by PML-RARalpha a translocation characteristic of acute promyelocytic leukemia (APL). Differentialy expressed proteins, a number of which are related to cell cycle function, including OP18, HSP70, GRP75 and Pin1 were identified by mass spectrometry. Further analysis of the OP18 pathway indicated that mRNA expression of OP18 was higher in APL patients and the increased OP18 protein expression upon PML-RAR induction was overcome by retinoic acid treatment. PML-RARalpha induced cell cycle progression and led to mitotic exit. RNA interference experiments revealed that siRNA against OP18 overcomes PML-RARalpha effects on cell cycle progression. In addition to increased OP18 expression by PML-RARalpha, 2D gel electrophoresis revealed an isomer of OP18, subsequently confirmed as Ser63 phosphomer to be downregulated by PML-RARalpha. Based on these findings, point mutation experiments indicated that decreased phosphorylation of Ser63 in OP18 is important for PML-RARalpha mediated cell cycle and mitotic index effects since constitutive phosphorylated mutant (Ser63-asp) of OP18 overcame the PML-RARalpha effects in U937-PR cells, NB4 and APL patients. In summary, our results demonstrate that the effect of PML-RAR on cell cycle progression and mitotic exit is via two mechanisms: increasing the expression of OP18 and decreasing the phosphorylation of OP18 at Ser63.
Item Type: | Theses (Dissertation, LMU Munich) |
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Keywords: | PML-RARalpha; proteomics; cell cycle; OP18; mass spectrometry; leukemia; |
Subjects: | 600 Technology, Medicine 600 Technology, Medicine > 610 Medical sciences and medicine |
Faculties: | Faculty of Medicine |
Language: | English |
Date of oral examination: | 15. December 2006 |
1. Referee: | Hiddemann, Wolfgang |
MD5 Checksum of the PDF-file: | 8b3d7358480cc59e882defa9fb0b64c2 |
Signature of the printed copy: | 0700/UMD 11945 |
ID Code: | 6320 |
Deposited On: | 13. Feb 2007 |
Last Modified: | 24. Oct 2020 08:54 |