Tracking hemopexin intracellularly and defining hemopexin protein "interactomes" in human immune and liver cell models.

ABSTRACT: Maintaining hemopexin (HPX) plasma levels protects against heme-activated inflammation as well as the toxicity of heme and its iron during hemolysis. Plasma heme regulates HPX turnover in hepatocytes, thus controlling plasma HPX concentration. Heme from heme-HPX is delivered to the liver, and apo-HPX recycles without degradation. The scavenger receptor, low-density lipoprotein-related protein 1 (LRP1), binds heme-HPX and targets it for lysosomal degradation. Nevertheless, heme-HPX endocytosis also occurs in mouse embryonic fibroblast LRP1^-/-PEA 13 cells. Therefore, the cell biology of heme-HPX endocytosis requires elucidation. We have identified candidate HPX receptors and human proteins that bind to heme-HPX, i.e., HPX "interactomes," in a human neutrophil model (promyelocytic

SUBMITTER: Rose B 

PROVIDER: S-EPMC12690290 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature