Calcium-dependent oligomerization of scavenger receptor CD163 facilitates the endocytosis of ligands.

ABSTRACT: Scavenger receptor CD163 is a marker of M2 type macrophages that play important roles in anti-inflammatory processes. The most extensively studied function of CD163 is related to the elimination of hemoglobin-haptoglobin (Hb-Hp) complexes, to prevent potential oxidative toxicity of the iron-containing heme. However, the structural mechanism of CD163 in ligand binding and internalization remains elusive. Here, we present the cryo-electron microscopy structure of human Hb-Hp recognition by the full ectodomain of CD163. We illuminate that CD163 forms calcium-dependent oligomers and primarily exists as trimeric form under the condition of 2.5 mM calcium. It mainly utilizes two protomers to interact with Hb-Hp complex asymmetrically, while the third protomer of the trimer also has the potential

SUBMITTER: Xu H 

PROVIDER: S-EPMC12279954 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature