- 作者: Diana V. Pastrana; Cheol H. Yun; Marian L. McKee; David J. FitzGerald
- 作者服務機構: Laboratory of Molecular Biology, CCR, National CancerInstitute, NIH, MD, USA
- 中文摘要: --
- 英文摘要: Low density lipoprotein receptor-related protein1, (LRP1) is a large multifunctional receptor that bindsmore than 25 physiologic ligands. In addition, it functionsas the surface receptor for several Rhinoviruses, HIV-tatand Pseudomonas exotoxin (PE). We report that theexpression of PE within mammalian cells can serve as aprobe of LRP1 maturation and functionality. To avoid cellkilling, an enzymatically inactive form of the toxin(PED553) was expressed. A permanent cell line (termedCY301) was established whereby PED553 was expressedcontinually into the ER of CHO cells. CY301 cells were100-fold resistant to exogenously added active PE butexhibited no cross-resistance to other toxins. Our studiesindicate that PED553 bound to immature LRP1 in the ER,prevented its maturation to the cell surface and therebyproduced a toxin resistant phenotype. By confocalmicroscopy, cell-associated PED553 was localized to theER and co-localized with LRP1. Further characterization ofCY301 cells indicated that RAP, the chaperone that aids inLRP1 folding, was released to the growth media. Thus theintracellular expression of PED553 appears to be a valuableprobe of LRP1 maturation and trafficking.
- 中文關鍵字: --
- 英文關鍵字: Toxin; Secretion; ERAD; Receptor; LRPI