Diva/BclB regulates differentiation by inhibiting NDPKB/Nm23H2-mediated neuronal differentiation in PC-12 cells.
BACKGROUND
Diva (death inducer binding to vBcl-2 and Apaf-1)/BclB is a Bcl-2 family member, which is known for its function in apoptosis. Diva/BclB has been shown to interact with NDPKB/Nm23H2, which is involved in cellular differentiation. Thus far, there has been no direct evidence of Diva/BclB having a role in differentiation. In the present study, we investigated the expression of Diva/BclB and NDPKB/Nm23H2 during differentiation in PC-12 cell line.


RESULTS
Our results show that after differentiation, Diva/BclB expression was decreased and reciprocally, NDPKB/Nm23H2 expression was increased and it translocated into the nucleus. Overexpression of NDPKB/Nm23H2 promoted PC-12 neuronal differentiation by increasing neurite outgrowth and arresting cell cycle progression. There was a concurrent downregulation of Diva/Boo when NDPKB/Nm23H2 was overexpressed, which mirrors the effect of NGF on PC-12 cell differentiation. Overexpression of Diva/BclB did not change the expression level of NDPKB/Nm23H2, but inhibited its nuclear localization. Cells that overexpressed Diva/BclB presented a decreased percentage of differentiated cells and average neurite length was shortened. This was due to an increase in the formation of Diva/BclB and NDPKB/Nm23H2 complexes as well as Diva/BclB and β-tubulin complexes. Concomitantly, there was a decrease in formation of NDPKB/Nm23H2 and β-tubulin complexes. Overexpression of Diva/BclB also resulted in a higher percentage of S-phase cells.


CONCLUSIONS
Our results showed a novel role for Diva/BclB in neuronal differentiation. Its downregulation during neuronal differentiation may be necessary to allow NDPKB/Nm23H2 and β-tubulin interaction that promotes NDPKB/Nm23H2 mediated differentiation.
Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore.
Jasmin Qian Ru
JQ
Lim
Jia
J
Lu
Bei Ping
BP
He
D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology; D054778:NM23 Nucleoside Diphosphate Kinases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D016501:Neurites / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D009701:Nucleoside-Diphosphate Kinase / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D016716:PC12 Cells; D021381:Protein Transport / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000502:physiology*; D051381:Rats; D015398:Signal Transduction / Q000502:physiology; D014404:Tubulin / Q000378:metabolism
C117144:BCL2-like 10 protein; D054778:NM23 Nucleoside Diphosphate Kinases; D019253:Proto-Oncogene Proteins c-bcl-2; D014404:Tubulin; D009701:Nucleoside-Diphosphate Kinase