Yi Jae-Sung, Lee Ji-Yeon, Chi Sung-Gil, Kim Ji-Hyun, Park Sang Gyu, Kim Sunghoon, Ko Young-Gyu
Graduate School of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Korea.
J Cell Biochem. 2005 Dec 15;96(6):1286-95. doi: 10.1002/jcb.20632.
An aminoacyl-tRNA synthetase subunit, p43, was previously demonstrated to be released from mammalian cells, and to function as an extracellular regulator of both angiogenesis and inflammatory responses (Ko et al., [2001] J Biol Chem, 276; 23028; Park et al.[2002], J Biol Chem 277; 45243). Here, we report that p43 is internalized to the endothelial cells via lipid rafts. Exogenous p43 was co-localized on bovine aorta endothelial cells with cholera toxin B (CTB), which binds to cholesterol-enriched lipid rafts. The p43 was rapidly internalized to the cells, as early as 5 min after binding to the surfaces of the cells. p43 bound to the isolated lipid rafts, and its interaction with the lipid rafts, was prevented by high salt content, but not by detergent. This suggests that ionic bonds are involved in the molecular association of p43 with the lipid rafts. Taken together, we conclude that p43 binds to the endothelial cell surface via lipid rafts.
一种氨酰 - tRNA合成酶亚基p43，先前已被证明可从哺乳动物细胞中释放出来，并作为血管生成和炎症反应的细胞外调节剂发挥作用（Ko等人，[2001]《生物化学杂志》，276；23028；Park等人[2002]，《生物化学杂志》277；45243）。在此，我们报告p43通过脂筏内化到内皮细胞中。外源性p43与霍乱毒素B（CTB）在牛主动脉内皮细胞上共定位，CTB与富含胆固醇的脂筏结合。p43早在与细胞表面结合5分钟后就迅速内化到细胞中。p43与分离的脂筏结合，其与脂筏的相互作用可被高盐含量阻止，但不能被去污剂阻止。这表明离子键参与了p43与脂筏的分子缔合。综上所述，我们得出结论，p43通过脂筏与内皮细胞表面结合。
