PDF(Pubmed)
Abstract：
Candida albicans and other closely related pathogenic yeast-like fungi carry on their surface numerous loosely adsorbed \"moonlighting proteins\"-proteins that play evolutionarily conserved intracellular functions but also appear on the cell surface and exhibit additional functions, e.g., contributing to attachment to host tissues. In the current work, we characterized this \"moonlighting\" role for glyceraldehyde 3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) of C. albicans and Nakaseomyces glabratus. GAPDH was directly visualized on the cell surface of both species and shown to play a significant part in the total capacity of fungal cells to bind two selected human host proteins-vitronectin and plasminogen. Using purified proteins, both host proteins were found to tightly interact with GAPDH, with dissociation constants in an order of 10-8 M, as determined by bio-layer interferometry and surface plasmon resonance measurements. It was also shown that exogenous GAPDH tightly adheres to the surface of candidal cells, suggesting that the cell surface location of this moonlighting protein may partly result from the readsorption of its soluble form, which may be present at an infection site (e.g., due to release from dying fungal cells). The major dedicated adhesins, covalently bound to the cell wall-agglutinin-like sequence protein 3 (Als3) and epithelial adhesin 6 (Epa6)-were suggested to serve as the docking platforms for GAPDH in C. albicans and N. glabratus, respectively.
摘要：
白色念珠菌和其他密切相关的致病性酵母样真菌在其表面携带许多松散吸附的“月光蛋白”-蛋白质，这些蛋白质发挥进化上保守的细胞内功能，但也出现在细胞表面并表现出额外的功能。例如，有助于附着于宿主组织。在目前的工作中,我们描述了甘油醛3-磷酸脱氢酶(GAPDH，EC1.2.1.12)的白色念珠菌和光亮纳酵母。GAPDH直接在两个物种的细胞表面上可视化，并显示在真菌细胞结合两种选定的人宿主蛋白-玻连蛋白和纤溶酶原的总能力中起重要作用。使用纯化的蛋白质，发现两种宿主蛋白都与GAPDH紧密相互作用，解离常数约为10-8M，通过生物层干涉测量和表面等离子体共振测量确定。还显示外源GAPDH紧密粘附在念珠菌细胞的表面，这表明这种月光下蛋白质的细胞表面位置可能部分是由于其可溶形式的重新吸附，可能存在于感染部位(例如，由于垂死的真菌细胞释放）。主要的忠实信徒，共价结合到细胞壁-凝集素样序列蛋白3（Als3）和上皮粘附素6（Epa6）-被认为是白色念珠菌和光亮奈瑟菌GAPDH的对接平台，分别。
