A secretory hexokinase plays an active role in the proliferation of <i>Nosema bombycis</i>

Abstract

The microsporidian <i>Nosema bombycis</i> is an obligate intracellular parasite of <i>Bombyx mori</i>, that lost its intact tricarboxylic acid cycle and mitochondria during evolution but retained its intact glycolysis pathway. <i>N. bombycis</i> 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 <i>N. bombycis</i> matured, NbHK tended to concentrate at the nuclei of host cells. Furthermore, the transcriptional profile of <i>NbHK</i> implied it functioned during <i>N. bombycis'</i> proliferation stages. A knock-down of <i>NbHK</i> effectively suppressed the proliferation of <i>N. bombycis</i> indicating that NbHK is an important protein for parasite to control its host.