Aminoacyl-tRNA synthetase-interacting multi-functional protein, p43, is imported to endothelial cells via lipid rafts.
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.
Yi
Jae-Sung
JS
Graduate School of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Korea.
Lee
Ji-Yeon
JY
Chi
Sung-Gil
SG
Kim
Ji-Hyun
JH
Park
Sang Gyu
SG
Kim
Sunghoon
S
Ko
Young-Gyu
YG
D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D002417:Cattle; D002772:Cholera Toxin / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism*; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism*; D008854:Microscopy, Electron; D011485:Protein Binding / Q000502:physiology; D021122:Protein Subunits / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology*
D021122:Protein Subunits; D002772:Cholera Toxin; D000604:Amino Acyl-tRNA Synthetases