Structure of an LDLR-RAP Complex Reveals a General Mode for Ligand Recognition by Lipoprotein Receptors

Fisher, Carl; Beglova, Natalia; Blacklow, Stephen C.

doi:10.1016/j.molcel.2006.02.021

Cited by 168 publications

(287 citation statements)

References 34 publications

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“…In addition to the negatively charged Asp and Glu side chains that coordinate calcium, additional acidic residues in the LDL receptor form a negatively charged surface in the folded protein that binds RAP and apoB (12,47). To bring such a large number of negative charges together during folding, small inorganic cations may be needed to prevent repulsion (55).…”

Section: Discussionmentioning

confidence: 99%

Calcium as a Crucial Cofactor for Low Density Lipoprotein Receptor Folding in the Endoplasmic Reticulum

Pena¹,

Jansens²,

Zadelhoff

et al. 2010

Journal of Biological Chemistry

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The family of low density lipoprotein (LDL) receptors mediate uptake of a plethora of ligands from the circulation and couple this to signaling, thereby performing a crucial role in physiological processes including embryonic development, cancer development, homeostasis of lipoproteins, viral infection, and neuronal plasticity. Structural integrity of individual ectodomain modules in these receptors depends on calcium, and we showed before that the LDL receptor folds its modules late after synthesis via intermediates with abundant non-native disulfide bonds and structure. Using a radioactive pulsechase approach, we here show that for proper LDL receptor folding, calcium had to be present from the very early start of folding, which suggests at least some native, essential coordination of calcium ions at the still largely non-native folding phase. As long as the protein was in the endoplasmic reticulum (ER), its folding was reversible, which changed only upon both proper incorporation of calcium and exit from the ER. Coevolution of protein folding with the high calcium concentration in the ER may be the basis for the need for this cation throughout the folding process even though calcium is only stably integrated in native repeats at a later stage.

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Section: Discussionmentioning

confidence: 99%

Calcium as a Crucial Cofactor for Low Density Lipoprotein Receptor Folding in the Endoplasmic Reticulum

Pena¹,

Jansens²,

Zadelhoff

et al. 2010

Journal of Biological Chemistry

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“…Two Lys residues in a receptor-binding domain of ␣2-macroglobulin have also been shown to be involved in binding to the LA module portion of LRP (27,28). Recent structural studies have revealed the ligand-recognition mechanism of LA modules at an atomic level (12,29,30). The most striking feature of the ligandrecognition mode was that in all cases Lys residues on structurally unrelated and dissimilar ligands were recognized by the conserved Ca-coordinating acidic residues and an aromatic residue from the LA modules (29).…”

Section: Discussionmentioning

confidence: 99%

“…Recent structural studies have revealed the ligand-recognition mechanism of LA modules at an atomic level (12,29,30). The most striking feature of the ligandrecognition mode was that in all cases Lys residues on structurally unrelated and dissimilar ligands were recognized by the conserved Ca-coordinating acidic residues and an aromatic residue from the LA modules (29). The present study reveals that reelin also falls into this class of ligands in which limited numbers of Lys residues (K2360 and K2467) are specifically recognized by an LA module.…”

Section: Discussionmentioning

confidence: 99%

Structure of a receptor-binding fragment of reelin and mutational analysis reveal a recognition mechanism similar to endocytic receptors

Yasui

Nogi

Kitao

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Reelin, a large secreted protein implicated in the cortical development of the mammalian brain, is composed of eight tandem concatenations of ''reelin repeats'' and binds to neuronal receptors belonging to the low-density lipoprotein receptor gene family. We found that both receptor-binding and subsequent Dab1 phosphorylation occur solely in the segment spanning the fifth and sixth reelin repeats (R5-6). Monomeric fragment exhibited a suboptimal level of signaling activity and artificial oligomerization resulted in a 10-fold increase in activity, indicating the critical importance of higher-order multimerization in physiological reelin. A 2.0-Å crystal structure from the R5-6 fragment revealed not only a unique domain arrangement wherein two repeats were aligned side by side with the same orientation, but also the unexpected presence of bound Zn ions. Structure-guided alanine mutagenesis of R5-6 revealed that two Lys residues (Lys-2360 and Lys-2467) constitute a central binding site for the low-density lipoprotein receptor class A module in the receptor, indicating a strong similarity to the ligand recognition mode shared among the endocytic lipoprotein receptors.brain development ͉ x-ray crystallography

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“…In an effort to circumvent problems intrinsic to whole cell studies, we have employed a solution assay in which binding is monitored by changes in inter-molecular fluorescence resonance energy transfer (FRET) between receptor and ligand [10]. In the present study, isoform specific binding of apoE to a recombinant soluble LDLR (sLDLR) and the effect of the molecular chaperone, Receptor Associated Protein (RAP) [11] on apoE receptor binding are described.…”

Section: Introductionmentioning

confidence: 99%

Apolipoprotein E isoform-specific binding to the low-density lipoprotein receptor

Yamamoto¹,

Choi²,

Ryan³

2008

Analytical Biochemistry

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Apolipoprotein E (apoE) is a ligand for members of the low-density lipoprotein receptor (LDLR) family and functions in plasma cholesterol homeostasis. A fluorescence-based assay has been employed in molecular studies of receptor-ligand interactions. Competition experiments revealed isoform specific differences in binding of lipid-associated apoE N terminal (NT) domain to a recombinant soluble LDLR (sLDLR). In a similar manner, lipid associated, but not lipid-free, fulllength apoE3 showed binding activity to sLDLR. The molecular chaperone, Receptor Associated Protein, inhibited apoE3-NT-phospholipid complex binding to sLDLR. Kinetic studies of apoE3-NT-phospholipid complex interaction with sLDLR revealed time dependent effects of apoE-NT isoform binding to sLDLR. The results reveal a discerning method for study of the molecular basis of ligand interactions that likely influence receptor function in maintenance of whole body cholesterol homeostasis.

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Structure of an LDLR-RAP Complex Reveals a General Mode for Ligand Recognition by Lipoprotein Receptors

Cited by 168 publications

References 34 publications

Calcium as a Crucial Cofactor for Low Density Lipoprotein Receptor Folding in the Endoplasmic Reticulum

Calcium as a Crucial Cofactor for Low Density Lipoprotein Receptor Folding in the Endoplasmic Reticulum

Structure of a receptor-binding fragment of reelin and mutational analysis reveal a recognition mechanism similar to endocytic receptors

Apolipoprotein E isoform-specific binding to the low-density lipoprotein receptor

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