Constrained glycopeptide ligands for MPRs. Limitations of unprotected phosphorylated building blocks

Franzyk, Henrik; Christensen, Mette K.; Jørgensen, Rikke Malene; Meldal, Morten; Cordes, Henriette; Mourit­sen, Søren; Bock, Klaus

doi:10.1016/s0968-0896(96)00194-0

Cited by 42 publications

(23 citation statements)

References 34 publications

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“…The bivalent ligand (Ac-Thr-[␣-D-Man-6-P(␣1-2)␣-D-Man]-Lys-(ABz)-Thr-[␣-D-Man-6-P(␣1-2)␣-D-Man]-NH 2 ) was kindly provided by Dr. K. Bock (Carlsberg Laboratory, Copenhagen, Denmark) (23).…”

Section: Methodsmentioning

confidence: 99%

The Rate of Internalization of the Mannose 6-Phosphate/Insulin-like Growth Factor II Receptor Is Enhanced by Multivalent Ligand Binding

York

Arneson

Gregory

et al. 1999

Journal of Biological Chemistry

105

117

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The cation-independent mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF-II receptor) undergoes constitutive endocytosis, mediating the internalization of two unrelated classes of ligands, mannose 6-phosphate (Man-6-P)-containing acid hydrolases and insulin-like growth factor II (IGF-II). To determine the role of ligand valency in M6P/IGF-II receptor-mediated endocytosis, we measured the internalization rates of two ligands, ␤-glucuronidase (a homotetramer bearing multiple Man-6-P moieties) and IGF-II. We found that ␤-glucuronidase entered the cell ϳ3-4-fold faster than IGF-II. Unlabeled ␤-glucuronidase stimulated the rate of internalization of 125 I-IGF-II to equal that of 125 I-␤-glucuronidase, but a bivalent synthetic tripeptide capable of occupying both Man-6-P-binding sites on the M6P/IGF-II receptor simultaneously did not. A mutant receptor with one of the two Man-6-P-binding sites inactivated retained the ability to internalize ␤-glucuronidase faster than IGF-II. Thus, the increased rate of internalization required a multivalent ligand and a single Man-6-P-binding site on the receptor. M6P/IGF-II receptor solubilized and purified in Triton X-100 was present as a monomer, but association with ␤-glucuronidase generated a complex composed of two receptors and one ␤-glucuronidase. Neither IGF-II nor the synthetic peptide induced receptor dimerization. These results indicate that intermolecular cross-linking of the M6P/IGF-II receptor occurs upon binding of a multivalent ligand, resulting in an increased rate of internalization.The mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF-II receptor) 1 is a type I transmembrane glycoprotein that cycles through the Golgi, endosomes, and the plasma membrane to carry out its role in the biogenesis of lysosomes and in the clearance of the polypeptide insulin-like growth factor II (IGF-II) (1, 2). In the Golgi, the receptor binds newly synthesized acid hydrolases modified with mannose 6-phosphate (Man-6-P) residues on their asparagine-linked oligosaccharides and transports them to endosomes via clathrincoated vesicles (3-5). The acid hydrolases are released in the acidified endosome and then packaged into lysosomes while the receptor either returns to the Golgi to bind another ligand or moves to the plasma membrane (6, 7). At the plasma membrane, the M6P/IGF-II receptor mediates internalization of Man-6-P-containing ligands and IGF-II (3,5,8).The interactions of IGF-II and Man-6-P-containing ligands with the M6P/IGF-II receptor have been characterized in several studies (8 -12). The extracellular portion of the M6P/ IGF-II receptor contains 15 homologous repeating domains of ϳ147 amino acids each (13). Domains 3 and 9 (numbering from the amino terminus) each bind 1 mol of Man-6-P, and the single IGF-II-binding site has been mapped to domain 11 in the extracellular region (14 -16). Man-6-P residues do not inhibit binding of IGF-II to the receptor, verifying that the two ligandbinding sites are distinct. However, proteins containing Man-6...

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Section: Methodsmentioning

confidence: 99%

The Rate of Internalization of the Mannose 6-Phosphate/Insulin-like Growth Factor II Receptor Is Enhanced by Multivalent Ligand Binding

York

Arneson

Gregory

et al. 1999

Journal of Biological Chemistry

105

117

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“…10 A series of synthetic multivalent ligands for the M6P/IGF2R was prepared by Bock and coworkers, using a glycopeptide design. 11 The best of these compounds bore two mannose disaccharides capped with phosphate connected by a core peptide of 3 to 5 amino acids. A tripeptide version of this compound bound the M6P/IGF2R with high affinity, which led to the hypothesis of a bivalent M6P-based mechanism.…”

mentioning

confidence: 99%

“…A tripeptide version of this compound bound the M6P/IGF2R with high affinity, which led to the hypothesis of a bivalent M6P-based mechanism. 5,11 However, upon closer inspection, it appears that the exceptional binding affinity of this compound was attributable to an anthranoyl group present on the lysine ε-amino group within the core peptide ( Figure 3). This modification increased the affinity by ~200-fold relative to the same compound with an unmodified peptide, 11 presumably through interaction with a hydrophobic patch on the receptor proximal to the M6P binding site.…”

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confidence: 99%

“…5,11 However, upon closer inspection, it appears that the exceptional binding affinity of this compound was attributable to an anthranoyl group present on the lysine ε-amino group within the core peptide ( Figure 3). This modification increased the affinity by ~200-fold relative to the same compound with an unmodified peptide, 11 presumably through interaction with a hydrophobic patch on the receptor proximal to the M6P binding site. Considering that the high affinity of this compound did not arise from a bivalent M6P-based binding mechanism, it is not surprising that York et al found that the compound failed to stabilize the receptor's dimeric structure or to stimulate its rapid internalization.…”

mentioning

confidence: 99%

“…The adventitious binding properties of the Bock compound suggest that additional binding energy may be achieved by adjusting hydrophobicity, charge and/or π-surface of the tether. 11 Moreover, the success enjoyed by the groups of Bock and Hindsgaul, respectively, in attaining 2-3 orders of magnitude improved receptor binding over M6P, suggests that peptide-or carbohydrate-based linkers may be advantageous. Both such tethers present H-bond donor/acceptor functionality across the M6P-M6P span.…”

mentioning

confidence: 99%

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A set of phosphatase-inert “molecular rulers” to probe for bivalent mannose 6-phosphate ligand–receptor interactions

Fei

Connelly

MacDonald

et al. 2008

Bioorganic & Medicinal Chemistry Letters

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A set of bivalent mannose 6-phosphonate "molecular rulers" has been synthesized to examine ligand binding to the M6P/IGF2R. The set is estimated to span a P-P distance range of 16-26 Å (MMFF energy minimization on the hydrated phosphonates). Key synthetic transformations include sugar triflate displacement for phosphonate installation and Grubbs I cross-metathesis to achieve bivalency. Relative binding affinities were tested by radioligand displacement assays versus PMP-BSA (pentamannose phosphate-bovine serum albumin). These compounds exhibit slightly higher binding affinities for the receptor (IC 50 's = 3.7-5 μM) than the parent, monomeric mannose 6-phosphonate ligand and M6P itself (IC 50 = 11.5 ± 2.5 μM). These results suggest that the use of an α-configured anomeric alkane tether is acceptable, as no significant thermodynamic penalty is apparently paid with this design. On the other hand, the modest gains in binding affinity observed suggest that this ligand set has not yet found true bivalent interaction with the M6P/IGF2R (i.e. binding to two distinct M6P-binding pockets).The mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R) is a type I transmembrane glycoprotein that cycles through the Golgi, endosomes, and the plasma membrane to carry out its role in the transport of lysosomal enzymes to their cellular destination. 1 The receptor also functions in the binding, uptake, and degradation of the mitogen, insulin-like growth factor II (IGF-II) and facilitates activation of the growth inhibitor, transforming growth factor-β. The ability of the M6P/IGF2R to inhibit cell proliferation, or stimulate apoptosis, by these mechanisms has implicated the receptor as a tumor suppressor. The IGF-II binding activity of the M6P/IGF2R is mainly responsible for its growth suppressor function. Many cancers become growth factor-independent by high-level expression of IGF-II, which not only binds to the M6P/IGF2R, but also to the IGF1R. The high affinity interaction of IGF-II with the IGF1R leads to activation of IGF1R signaling pathways that promote cell division and survival.2 § Note: These authors contributed equally to this work. Supplementary dataExperimental procedures, spectral data, copies of NMR spectra and details of the radioligand displacement assays can be found in the online version at ____.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. (Figure 1). Importantly, they also observed that hGUS binding increased the rate of internalization of the receptor and consequently stimulated the degradation of any passenger ligands, including IGF-II, by 3...

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Organische Synthese und biologische Signaltransduktion

Hinterding¹,

Alonso-Díaz²,

Waldmann³

1998

Angewandte Chemie

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Das Verständnis zellulärer Kommunikationswege im molekularen Detail ist ein wichtiges Ziel bioorganischer Forschung. Die Synthese von Wirkstoffanaloga (z. B. 1) zum Studium der Regulation der Muskelkontraktion oder die spezifische Lipidmodifizierung repräsentativer Peptide (→2) zur Untersuchung ihrer subzellulären Adressierung zu intrazellulären Membranen – dies sind Beispiele für die Leistungsfähigkeit der organischen Synthese bei der Erforschung biologischer Signaltransduktionsmechanismen.

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Constrained glycopeptide ligands for MPRs. Limitations of unprotected phosphorylated building blocks

Cited by 42 publications

References 34 publications

The Rate of Internalization of the Mannose 6-Phosphate/Insulin-like Growth Factor II Receptor Is Enhanced by Multivalent Ligand Binding

The Rate of Internalization of the Mannose 6-Phosphate/Insulin-like Growth Factor II Receptor Is Enhanced by Multivalent Ligand Binding

A set of phosphatase-inert “molecular rulers” to probe for bivalent mannose 6-phosphate ligand–receptor interactions

Organische Synthese und biologische Signaltransduktion

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