Laurian Romain, Ravent Jade, Dementhon Karine, Lemaire Marc, Soulard Alexandre, Cotton Pascale
INSA Lyon, CNRS, Université de Lyon, Université Claude Bernard Lyon1, UMR5240 MAP, 69622 Villeurbanne, France.
UMR-CNRS 5234, Laboratoire de Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, 33076 Bordeaux, France.
Microorganisms. 2021 Apr 15;9(4):848. doi: 10.3390/microorganisms9040848.
Survival of the pathogenic yeast depends upon assimilation of fermentable and non-fermentable carbon sources detected in host microenvironments. Among the various carbon sources encountered in a human body, glucose is the primary source of energy. Its effective detection, metabolism and prioritization via glucose repression are primordial for the metabolic adaptation of the pathogen. In glucose phosphorylation is mainly performed by the hexokinase 2 (Hxk2). In addition, in the presence of glucose, HxK2 migrates in the nucleus and contributes to the glucose repression signaling pathway. Based on the known dual function of the hexokinase 2 (Hxk2), we intended to explore the impact of both enzymatic and regulatory functions of Hxk2 on virulence, using a site-directed mutagenesis approach. We show that the conserved aspartate residue at position 210, implicated in the interaction with glucose, is essential for enzymatic and glucose repression functions but also for filamentation and virulence in macrophages. Point mutations and deletion into the -terminal region known to specifically affect glucose repression in Hxk2 proved to be ineffective in Hxk2. These results clearly show that enzymatic and regulatory functions of the hexokinase 2 cannot be unlinked in
致病性酵母的存活取决于其对在宿主微环境中检测到的可发酵和不可发酵碳源的同化作用。在人体中遇到的各种碳源中，葡萄糖是主要的能量来源。通过葡萄糖阻遏对其进行有效的检测、代谢和优先级排序对于病原体的代谢适应至关重要。在[具体情况未提及]中，葡萄糖磷酸化主要由己糖激酶2（Hxk2）进行。此外，在有葡萄糖存在的情况下，HxK2会迁移到细胞核中，并参与葡萄糖阻遏信号通路。基于己糖激酶2（Hxk2）已知的双重功能，我们打算使用定点诱变方法来探究Hxk2的酶促功能和调节功能对毒力的影响。我们发现，与葡萄糖相互作用相关的第210位保守天冬氨酸残基对于酶促功能和葡萄糖阻遏功能至关重要，对于巨噬细胞中的丝状化和毒力也至关重要。已知特异性影响Hxk2中葡萄糖阻遏的-末端区域的点突变和缺失在Hxk2中被证明是无效的。这些结果清楚地表明，己糖激酶2的酶促功能和调节功能在[具体情况未提及]中无法分开。
