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Viruses. 2016 May 12;8(5). pii: E131. doi: 10.3390/v8050131.

Protein 2B of Coxsackievirus B3 Induces Autophagy Relying on Its Transmembrane Hydrophobic Sequences.

Author information

1
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. wuheng1990@163.com.
2
Department of Reproductive Medicine, The First Hospital of Harbin Medical University, 23 Youzheng Street, Harbin 150001, China. wuheng1990@163.com.
3
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. zhai_xia_cool@126.com.
4
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. cy_hmu@126.com.
5
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. katekitekite@163.com.
6
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. linlexun@163.com.
7
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. chensj0802@163.com.
8
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. wangty0929@163.com.
9
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. littlerock712@163.com.
10
Department of Cardiology, The First Hospital of Harbin Medical University, 23 Youzheng Street, Harbin 150001, China. xiaoyu_wu2006@163.com.
11
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. wangyan@hrbmu.edu.cn.
12
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. fengminzhang@ems.hrbmu.edu.cn.
13
Department of Cell Biology, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. zhaowr@ems.hrbmu.edu.cn.
14
Department of Microbiology and Wu Lien-Teh Institute, Harbin Medical University, 157 Baojian Road, Harbin 150081, China. zhongzh@hrbmu.edu.cn.

Abstract

Coxsackievirus B (CVB) belongs to Enterovirus genus within the Picornaviridae family, and it is one of the most common causative pathogens of viral myocarditis in young adults. The pathogenesis of myocarditis caused by CVB has not been completely elucidated. In CVB infection, autophagy is manipulated to facilitate viral replication. Here we report that protein 2B, one of the non-structural proteins of CVB3, possesses autophagy-inducing capability. The autophagy-inducing motif of protein 2B was identified by the generation of truncated 2B and site-directed mutagenesis. The expression of 2B alone was sufficient to induce the formation of autophagosomes in HeLa cells, while truncated 2B containing the two hydrophobic regions of the protein also induced autophagy. In addition, we demonstrated that a single amino acid substitution (56V→A) in the stem loop in between the two hydrophobic regions of protein 2B abolished the formation of autophagosomes. Moreover, we found that 2B and truncated 2B with autophagy-inducting capability were co-localized with LC3-II. This study indicates that protein 2B relies on its transmembrane hydrophobic regions to induce the formation of autophagosomes, while 56 valine residue in the stem loop of protein 2B might exert critical structural influence on its two hydrophobic regions. These results may provide new insight for understanding the molecular mechanism of autophagy triggered by CVB infection.

KEYWORDS:

autophagy; coxsackievirus B3; protein 2B; transmembrane hydrophobic sequence

PMID:
27187444
PMCID:
PMC4885086
DOI:
10.3390/v8050131
[Indexed for MEDLINE]
Free PMC Article

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