Department of Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.
Department of Anatomy and Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
J Biol Chem. 2023 Apr;299(4):104607. doi: 10.1016/j.jbc.2023.104607. Epub 2023 Mar 15.
The glycolipid transfer protein (GLTP) has been linked to many cellular processes aside from its best-known in vitro function as a lipid transport protein. It has been proposed to act as a sensor and regulator of glycosphingolipid homeostasis in cells. Furthermore, through its previously determined interaction with the endoplasmic reticulum membrane protein VAP-A (vesicle-associated membrane protein-associated protein A), GLTP may also be involved in facilitating vesicular transport in cells. In this study, we characterized the phenotype of CRISPR/Cas9-mediated GLTP KO HeLa cells. We showed that motility, three-dimensional growth, and cellular metabolism were all altered by GLTP knockout. Expression of a GLTP mutant incapable of binding VAP disrupted cell spheroid formation, indicating that the GLTP-VAP interaction is linked to cellular adhesion, cohesion, and three-dimensional growth. Most notably, we found evidence that GLTP, through its interaction with VAP-A, affects vesicular trafficking, marking the first cellular process discovered to be directly impacted by a change in GLTP expression.
糖脂转移蛋白 (GLTP) 除了其作为脂质转运蛋白的最知名的体外功能外，还与许多细胞过程有关。它被提议作为细胞中糖脂稳态的传感器和调节剂。此外，通过其先前确定的与内质网膜蛋白 VAP-A（囊泡相关膜蛋白相关蛋白 A）的相互作用，GLTP 也可能参与细胞内囊泡运输的促进。在这项研究中，我们对 CRISPR/Cas9 介导的 GLTP KO HeLa 细胞的表型进行了表征。我们表明，运动性、三维生长和细胞代谢都因 GLTP 缺失而改变。不能结合 VAP 的 GLTP 突变体的表达破坏了细胞球体的形成，表明 GLTP-VAP 相互作用与细胞黏附、黏附和三维生长有关。最值得注意的是，我们发现证据表明，GLTP 通过与 VAP-A 的相互作用影响囊泡运输，这标志着发现的第一个受 GLTP 表达变化直接影响的细胞过程。
