Scavenger receptors are a large, structurally diverse group of integral membrane and soluble secreted proteins. Scavenger receptors bind to a broad array of polyanionic ligands such as bacteria, apoptotic cell debris, and modified low-density lipoproteins. Based on their multi-domain architecture, scavenger receptors are grouped into classes; members within each class share sequence similarity but different classes bear little or no primary sequence similarity. (Adapted from FBrf0188507, PMID:19388903 and PMID:26010753.)