| Structural highlights
Disease
CD40L_HUMAN Defects in CD40LG are the cause of X-linked immunodeficiency with hyper-IgM type 1 (HIGM1) [MIM:308230; also known as X-linked hyper IgM syndrome (XHIM). HIGM1 is an immunoglobulin isotype switch defect characterized by elevated concentrations of serum IgM and decreased amounts of all other isotypes. Affected males present at an early age (usually within the first year of life) recurrent bacterial and opportunistic infections, including Pneumocystis carinii pneumonia and intractable diarrhea due to cryptosporidium infection. Despite substitution treatment with intravenous immunoglobulin, the overall prognosis is rather poor, with a death rate of about 10% before adolescence.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
Function
CD40L_HUMAN Mediates B-cell proliferation in the absence of co-stimulus as well as IgE production in the presence of IL-4. Involved in immunoglobulin class switching.[11] Release of soluble CD40L from platelets is partially regulated by GP IIb/IIIa, actin polymerization, and an matrix metalloproteinases (MMP) inhibitor-sensitive pathway.[12]
Publication Abstract from PubMed
BIO8898 is one of several synthetic organic molecules that have recently been reported to inhibit receptor binding and function of the constitutively trimeric tumor necrosis factor (TNF) family cytokine CD40 ligand (CD40L, aka CD154). Small molecule inhibitors of protein-protein interfaces are relatively rare, and their discovery is often very challenging. Therefore, to understand how BIO8898 achieves this feat, we characterized its mechanism of action using biochemical assays and X-ray crystallography. BIO8898 inhibited soluble CD40L binding to CD40-Ig with a potency of IC(50) = 25 muM and inhibited CD40L-dependent apoptosis in a cellular assay. A co-crystal structure of BIO8898 with CD40L revealed that one inhibitor molecule binds per protein trimer. Surprisingly, the compound binds not at the surface of the protein but by intercalating deeply between two subunits of the homotrimeric cytokine, disrupting a constitutive protein-protein interface and breaking the protein's 3-fold symmetry. The compound forms several hydrogen bonds with the protein, within an otherwise hydrophobic binding pocket. In addition to the translational splitting of the trimer, binding of BIO8898 was accompanied by additional local and longer-range conformational perturbations of the protein, both in the core and in a surface loop. Binding of BIO8898 is reversible, and the resulting complex is stable and does not lead to detectable dissociation of the protein trimer. Our results suggest that a set of core aromatic residues that are conserved across a subset of TNF family cytokines might represent a generic hot-spot for the induced-fit binding of trimer-disrupting small molecules.
Small Molecule Inhibition of the TNF Family Cytokine CD40 Ligand through a Subunit Fracture Mechanism.,Silvian LF, Friedman JE, Strauch K, Cachero TG, Day ES, Qian F, Cunningham B, Fung A, Sun L, Su L, Zheng Z, Kumaravel G, Whitty A ACS Chem Biol. 2011 Jun 17;6(6):636-47. Epub 2011 Apr 20. PMID:21417339[13]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Aruffo A, Farrington M, Hollenbaugh D, Li X, Milatovich A, Nonoyama S, Bajorath J, Grosmaire LS, Stenkamp R, Neubauer M, et al.. The CD40 ligand, gp39, is defective in activated T cells from patients with X-linked hyper-IgM syndrome. Cell. 1993 Jan 29;72(2):291-300. PMID:7678782
- ↑ Korthauer U, Graf D, Mages HW, Briere F, Padayachee M, Malcolm S, Ugazio AG, Notarangelo LD, Levinsky RJ, Kroczek RA. Defective expression of T-cell CD40 ligand causes X-linked immunodeficiency with hyper-IgM. Nature. 1993 Feb 11;361(6412):539-41. PMID:7679206 doi:http://dx.doi.org/10.1038/361539a0
- ↑ DiSanto JP, Bonnefoy JY, Gauchat JF, Fischer A, de Saint Basile G. CD40 ligand mutations in x-linked immunodeficiency with hyper-IgM. Nature. 1993 Feb 11;361(6412):541-3. PMID:8094231 doi:http://dx.doi.org/10.1038/361541a0
- ↑ Allen RC, Armitage RJ, Conley ME, Rosenblatt H, Jenkins NA, Copeland NG, Bedell MA, Edelhoff S, Disteche CM, Simoneaux DK, et al.. CD40 ligand gene defects responsible for X-linked hyper-IgM syndrome. Science. 1993 Feb 12;259(5097):990-3. PMID:7679801
- ↑ Macchi P, Villa A, Strina D, Sacco MG, Morali F, Brugnoni D, Giliani S, Mantuano E, Fasth A, Andersson B, et al.. Characterization of nine novel mutations in the CD40 ligand gene in patients with X-linked hyper IgM syndrome of various ancestry. Am J Hum Genet. 1995 Apr;56(4):898-906. PMID:7717401
- ↑ Saiki O, Tanaka T, Wada Y, Uda H, Inoue A, Katada Y, Izeki M, Iwata M, Nunoi H, Matsuda I, et al.. Signaling through CD40 rescues IgE but not IgG or IgA secretion in X-linked immunodeficiency with hyper-IgM. J Clin Invest. 1995 Feb;95(2):510-4. PMID:7532185 doi:http://dx.doi.org/10.1172/JCI117692
- ↑ Katz F, Hinshelwood S, Rutland P, Jones A, Kinnon C, Morgan G. Mutation analysis in CD40 ligand deficiency leading to X-linked hypogammaglobulinemia with hyper IgM syndrome. Hum Mutat. 1996;8(3):223-8. PMID:8889581 doi:<223::AID-HUMU5>3.0.CO;2-A 10.1002/(SICI)1098-1004(1996)8:3<223::AID-HUMU5>3.0.CO;2-A
- ↑ Lin Q, Rohrer J, Allen RC, Larche M, Greene JM, Shigeoka AO, Gatti RA, Derauf DC, Belmont JW, Conley ME. A single strand conformation polymorphism study of CD40 ligand. Efficient mutation analysis and carrier detection for X-linked hyper IgM syndrome. J Clin Invest. 1996 Jan 1;97(1):196-201. PMID:8550833 doi:http://dx.doi.org/10.1172/JCI118389
- ↑ Nonoyama S, Shimadzu M, Toru H, Seyama K, Nunoi H, Neubauer M, Yata J, Och HD. Mutations of the CD40 ligand gene in 13 Japanese patients with X-linked hyper-IgM syndrome. Hum Genet. 1997 May;99(5):624-7. PMID:9150729
- ↑ Seyama K, Nonoyama S, Gangsaas I, Hollenbaugh D, Pabst HF, Aruffo A, Ochs HD. Mutations of the CD40 ligand gene and its effect on CD40 ligand expression in patients with X-linked hyper IgM syndrome. Blood. 1998 Oct 1;92(7):2421-34. PMID:9746782
- ↑ Furman MI, Krueger LA, Linden MD, Barnard MR, Frelinger AL 3rd, Michelson AD. Release of soluble CD40L from platelets is regulated by glycoprotein IIb/IIIa and actin polymerization. J Am Coll Cardiol. 2004 Jun 16;43(12):2319-25. PMID:15193700 doi:10.1016/j.jacc.2003.12.055
- ↑ Furman MI, Krueger LA, Linden MD, Barnard MR, Frelinger AL 3rd, Michelson AD. Release of soluble CD40L from platelets is regulated by glycoprotein IIb/IIIa and actin polymerization. J Am Coll Cardiol. 2004 Jun 16;43(12):2319-25. PMID:15193700 doi:10.1016/j.jacc.2003.12.055
- ↑ Silvian LF, Friedman JE, Strauch K, Cachero TG, Day ES, Qian F, Cunningham B, Fung A, Sun L, Su L, Zheng Z, Kumaravel G, Whitty A. Small Molecule Inhibition of the TNF Family Cytokine CD40 Ligand through a Subunit Fracture Mechanism. ACS Chem Biol. 2011 Jun 17;6(6):636-47. Epub 2011 Apr 20. PMID:21417339 doi:10.1021/cb2000346
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