Reed R C, Nicchitta C V
Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
Int J Mol Med. 2000 Sep;6(3):259-64. doi: 10.3892/ijmm.6.3.259.
The resident endoplasmic reticulum (ER) chaperone proteins GRP94 (gp96) and calreticulin can activate the immune system to slow or stop the progression of tumors by escorting tumor-derived peptides into the endogenous antigen presentation pathway of antigen presenting cells (APC). Although the phenomenology of cross-priming is well worked out, the mechanism(s) remains unclear. Continuing insights into cellular protein trafficking pathways suggest several means by which chaperones could travel from the extracellular space into the endosome, lysosome or ER of APC. In particular, proteins that cycle between two or more compartments and those that undergo and mediate retrograde flow offer models of how exogenous chaperones might travel in the APC. New insights into how non-chaperone proteins access the APC antigen presentation pathway also suggest several ways this process could occur.
内质网驻留伴侣蛋白GRP94（gp96）和钙网蛋白可通过将肿瘤衍生肽护送进入抗原呈递细胞（APC）的内源性抗原呈递途径，激活免疫系统以减缓或阻止肿瘤进展。尽管交叉呈递的现象学已得到充分研究，但其机制仍不清楚。对细胞蛋白质运输途径的不断深入了解提示了伴侣蛋白从细胞外空间进入APC的内体、溶酶体或内质网的几种方式。特别是，在两个或更多区室之间循环的蛋白质以及经历并介导逆行流动的蛋白质，为外源性伴侣蛋白在APC中可能的运输方式提供了模型。对非伴侣蛋白如何进入APC抗原呈递途径的新见解也提示了该过程可能发生的几种方式。
