Phosphorylation of hepatitis B virus core C-terminally truncated protein (Cp149) by PKC increases capsid assembly and stability

2008 ◽  
Vol 416 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Hang Kang ◽  
Jaehoon Yu ◽  
Guhung Jung

The HBV (hepatitis B virus) core is a phosphoprotein whose assembly, replication, encapsidation and localization are regulated by phosphorylation. It is known that PKC (protein kinase C) regulates pgRNA (pregenomic RNA) encapsidation by phosphorylation of the C-terminus of core, which is a component packaged into capsid. Neither the N-terminal residue phosphorylated by PKC nor the role of the C-terminal phosphorylation have been cleary defined. In the present study we found that HBV Cp149 (core protein C-terminally truncated at amino acid 149) expressed in Escherichia coli was phosphorylated by PKC at Ser106. PKC-mediated phosphorylation increased core affinity, as well as assembly and capsid stability. In vitro phosphorylation with core mutants (S26A, T70A, S106A and T114A) revealed that the Ser106 mutation inhibited phosphorylation of core by PKC. CD analysis also revealed that PKC-mediated phosphorylation stabilized the secondary structure of capsid. When either pCMV/FLAG-Cp149[WT (wild-type)] or pCMV/FLAG-S106A Cp149 was transfected into Huh7 human hepatoma cells, mutant capsid level was decreased by 2.06-fold with the S106A mutant when compared with WT, although the same level of total protein was expressed in both cases. In addition, when pUC1.2x and pUC1.2x/S106A were transfected, mutant virus titre was decreased 2.31-fold compared with WT virus titre. In conclusion, PKC-mediated phosphorylation increased capsid assembly, stability and structural stability.

2015 ◽  
Vol 25 (2) ◽  
pp. 363-369 ◽  
Author(s):  
Yawen Wang ◽  
Yiping Li ◽  
Na Li ◽  
Qianqian Zhu ◽  
Lingyun Hui ◽  
...  

2020 ◽  
Vol 432 (13) ◽  
pp. 3802-3819 ◽  
Author(s):  
Virgile Rat ◽  
Xavier Pinson ◽  
Florian Seigneuret ◽  
Stéphanie Durand ◽  
Charline Herrscher ◽  
...  

2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Jan Martin Berke ◽  
Pascale Dehertogh ◽  
Karen Vergauwen ◽  
Wendy Mostmans ◽  
Koen Vandyck ◽  
...  

ABSTRACT Capsid assembly is a critical step in the hepatitis B virus (HBV) life cycle, mediated by the core protein. Core is a potential target for new antiviral therapies, the capsid assembly modulators (CAMs). JNJ-56136379 (JNJ-6379) is a novel and potent CAM currently in phase II trials. We evaluated the mechanisms of action (MOAs) and antiviral properties of JNJ-6379 in vitro. Size exclusion chromatography and electron microscopy studies demonstrated that JNJ-6379 induced the formation of morphologically intact viral capsids devoid of genomic material (primary MOA). JNJ-6379 accelerated the rate and extent of HBV capsid assembly in vitro. JNJ-6379 specifically and potently inhibited HBV replication; its median 50% effective concentration (EC50) was 54 nM (HepG2.117 cells). In HBV-infected primary human hepatocytes (PHHs), JNJ-6379, when added with the viral inoculum, dose-dependently reduced extracellular HBV DNA levels (median EC50 of 93 nM) and prevented covalently closed circular DNA (cccDNA) formation, leading to a dose-dependent reduction of intracellular HBV RNA levels (median EC50 of 876 nM) and reduced antigen levels (secondary MOA). Adding JNJ-6379 to PHHs 4 or 5 days postinfection reduced extracellular HBV DNA and did not prevent cccDNA formation. Time-of-addition PHH studies revealed that JNJ-6379 most likely interfered with postentry processes. Collectively, these data demonstrate that JNJ-6379 has dual MOAs in the early and late steps of the HBV life cycle, which is different from the MOA of nucleos(t)ide analogues. JNJ-6379 is in development for chronic hepatitis B treatment and may translate into higher HBV functional cure rates.


Biochemistry ◽  
2014 ◽  
Vol 53 (34) ◽  
pp. 5496-5504 ◽  
Author(s):  
Lisa Selzer ◽  
Sarah P. Katen ◽  
Adam Zlotnick

2004 ◽  
Vol 189 (9) ◽  
pp. 1634-1645 ◽  
Author(s):  
Mohammed S. Jazayeri ◽  
Edward S. Dornan ◽  
Winifred Boner ◽  
Giovanna Fattovich ◽  
Stephanos Hadziyannis ◽  
...  

2019 ◽  
Vol 263 ◽  
pp. 102-111 ◽  
Author(s):  
Hyun Wook Seo ◽  
Joon Pyung Seo ◽  
Yuri Cho ◽  
Eunkyong Ko ◽  
Yoon Jun Kim ◽  
...  

2003 ◽  
Vol 66 (12) ◽  
pp. 2273-2279 ◽  
Author(s):  
Hans Jörg Hacker ◽  
Karl Deres ◽  
Maria Mildenberger ◽  
Claus H. Schröder

Sign in / Sign up

Export Citation Format

Share Document