Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
Doctoral School of Exact and Natural Sciences, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
Int J Mol Sci. 2024 Jan 13;25(2):1013. doi: 10.3390/ijms25021013.
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 and . 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 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 and , respectively.
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”——这些蛋白质在进化上具有保守的细胞内功能,但也出现在细胞表面并表现出额外的功能,例如,有助于与宿主组织的附着。在目前的工作中,我们对 和 的甘油醛 3-磷酸脱氢酶(GAPDH,EC 1.2.1.12)的这种“月光”作用进行了表征。在这两个物种的细胞表面都可以直接观察到 GAPDH,并表明它在真菌细胞结合两种选定的人类宿主蛋白——纤连蛋白和纤溶酶原的总能力中起着重要作用。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,通过生物层干涉测量和表面等离子体共振测量确定的解离常数在 10 M 左右。还表明外源性 GAPDH 紧密附着在念珠菌细胞表面,表明这种月光蛋白的细胞表面位置部分可能是由于其可溶性形式的再吸附所致,该形式可能存在于感染部位(例如,由于死亡真菌细胞的释放)。建议将共价结合到细胞壁上的主要专用粘附素,凝集素样序列蛋白 3(Als3)和上皮粘附素 6(Epa6),分别作为 和 中 GAPDH 的对接平台。