5ew6 | pdb_00005ew6
Structure of ligand binding region of uPARAP at pH 7.4 without calcium
Structural highlights
Function[MRC2_HUMAN] May play a role as endocytotic lectin receptor displaying calcium-dependent lectin activity. Internalizes glycosylated ligands from the extracellular space for release in an endosomal compartment via clathrin-mediated endocytosis. May be involved in plasminogen activation system controlling the extracellular level of PLAUR/PLAU, and thus may regulate protease activity at the cell surface. May contribute to cellular uptake, remodeling and degradation of extracellular collagen matrices. May play a role during cancer progression as well as in other chronic tissue destructive diseases acting on collagen turnover. May participate in remodeling of extracellular matrix cooperating with the matrix metalloproteinases (MMPs).[1] [2] Publication Abstract from PubMedThe proteins of the mannose receptor (MR) family share a common domain organization and have a broad range of biological functions. Urokinase plasminogen activator receptor-associated protein (uPARAP) (or Endo180) is a member of this family and plays an important role in extracellular matrix remodelling through interaction with its ligands, including collagens and urokinase plasminogen activator receptor (uPAR). We report the crystal structures of the first four domains of uPARAP (also named the ligand-binding region, LBR) at pH 7.4 in Ca(2+)-bound and Ca(2+)-free forms. The first domain (cysteine-rich or CysR domain) folds into a new and unique conformation different from the beta-trefoil fold of typical CysR domains. The so-called long loop regions (LLRs) of the C-type lectin-like domain (CTLD) 1 and 2 (the third and fourth domain) mediate the direct contacts between these domains. These LLRs undergo a Ca(2+)-dependent conformational change, and this is likely to be the key structural determinant affecting the overall conformation of uPARAP. Our results provide a molecular mechanism to support the structural flexibility of uPARAP, and shed light on the structural flexibility of other members of the MR family. Crystal structures of the ligand-binding region of uPARAP: effect of calcium ion binding.,Yuan C, Jurgensen HJ, Engelholm LH, Li R, Liu M, Jiang L, Luo Z, Behrendt N, Huang M Biochem J. 2016 Aug 1;473(15):2359-68. doi: 10.1042/BCJ20160276. Epub 2016 May, 31. PMID:27247422[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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