Fig. 9: Proposed mechanism of CD163-mediated endocytosis of Hb-bound Hp oligomers. | Nature Communications

Fig. 9: Proposed mechanism of CD163-mediated endocytosis of Hb-bound Hp oligomers.

From: The Cryo-EM structure of human CD163 bound to haptoglobin-hemoglobin reveals molecular mechanisms of hemoglobin scavenging

Fig. 9

On the surface of the cell, CD163 forms Ca2+-dependent oligomers that binds Hp(1-1)Hb, Hp(2-1)Hb, or Hp(2-2)Hb. After endocytosis, lowering of the Ca2+ concentration and pH in the late endosome causes CD163 dissociation and HpHb release. Monomeric CD163 is recycled back to the plasma membrane where the CD163 trimer is reestablished while HpHb is degraded in the lysosome. CD163 shed from the membrane may dissociate into CD163 monomers with low affinity for HpHb.

Back to article page