A secretory hexokinase plays an active role in the proliferation of Nosema bombycis.

Yukang Huang,Jie Chen,Zeyang Zhou,Tian Li,Chunfeng Li,Xionge Mei,Junhong Wei,Bin Yu,Guoqing Pan,Bin Sun,Shiyi Zheng,Boning Li

doi:10.7717/peerj.5658

Yukang Huang, Jie Chen + Show 10 more

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https://doi.org/10.7717/peerj.5658

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Journal: PeerJ	Publication Date: Sep 21, 2018
Citations: 33	License type: CC BY 4.0

Affiliation: Southwest University, Chongqing Normal University

Abstract

The microsporidian Nosema bombycis is an obligate intracellular parasite of Bombyx mori, that lost its intact tricarboxylic acid cycle and mitochondria during evolution but retained its intact glycolysis pathway. N. bombycis hexokinase (NbHK) is not only a rate-limiting enzyme of glycolysis but also a secretory protein. Indirect immunofluorescence assays and recombinant HK overexpressed in BmN cells showed that NbHK localized in the nucleus and cytoplasm of host cell during the meront stage. When N. bombycis matured, NbHK tended to concentrate at the nuclei of host cells. Furthermore, the transcriptional profile of NbHK implied it functioned during N. bombycis’ proliferation stages. A knock-down of NbHK effectively suppressed the proliferation of N. bombycis indicating that NbHK is an important protein for parasite to control its host.

Highlights

Microsporidia are unicellular eukaryotes and obligate intracellular parasites that have broad host range (Cali & Takvorian, 1999)
Most microsporidia no longer have an intact tricarboxylic acid cycle or mitochondria, which implies an acute dependence on host energy during the intracellular stage (Hacker et al, 2014)
The amino acid sequence analysis showed that N. bombycis hexokinase (NbHK) contained a signal peptide, which implied it was a secretory protein (Fig. 1A)

Summary

Introduction

Microsporidia are unicellular eukaryotes and obligate intracellular parasites that have broad host range (Cali & Takvorian, 1999). The life cycle of a microsporidia can be divided into the dormant extracellular and intracellular proliferation stages (Bigliardi & Sacchi, 2001). Most microsporidia no longer have an intact tricarboxylic acid cycle or mitochondria, which implies an acute dependence on host energy during the intracellular stage (Hacker et al, 2014). Some microsporidia still maintain their intact glycolytic pathways, which may function during the extracellular stage (Wiredu et al, 2017).

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