Receptor-Binding Proteins

HA is a trimer. The monomers are not covalently linked and have a length of about 560 amino acids. At the C-terminus, a short cytoplasmic tail of 10 amino acids is followed by a stretch of about 27 hydrophobic residues that anchors HA in the membrane. The ectodomain of the HA of strain A/Aichi/68 can be released by bromelain treatment of the virus and was used to determine the three-dimensional structure by X-ray crystallography to 3 A resolution (Wilson et al., 1981). These studies indicated that the influenza HA extends 135 A from the viral lipid bilayer and consists of two major elements. The membrane proximal portion has been described as an elongated stem comprising the HA2 and part of the HAj subunit. On top of this stem, there is a globular domain 

---

Organism Outer membrane receptor Binding protein Membrane component ATP-binding component Substrates References... 

Spinelli, S., Desmyter, A., Verrips, G. T., de Haard, H. J., Moineau, S., and Cambillau, C. (2006). Lactococcal bacteriophage P2 receptor-binding protein structure suggests a common ancestor gene with bacterial and mammalian viruses. Nat. Struct. Mol. Biol. 13, 85-89. 

Xu, L., Benson, S. D., Butcher, S. J., Bamford, D. H., and Burnett, R. M. (2003). The receptor binding protein P2 of PRD1, a virus targeting santibiotic-resistant bacteria, has a novel fold suggesting multiple functions. Structure 11, 309-322. 

Lindberg, F., Lund, B., Johansson, L., and Normark, S. (1987). Localization of the receptor-binding protein adhesin at the tip of the bacterial pilus. Nature 328,84-87. 

Grb2p Growth factor receptor binding protein-2fS... 

Luginger E, Wenning GK, BOsch S, Poewe W (2000) Beneficial effects of amantadine on L-dopa-induced dyskinesias in Parkinson s disease. Mov Disord 15 873-878 Ly CD, Roche KW, Lee HK, Wenthold RJ (2002) Identification of rat EMAP, a delta-glutamate receptor binding protein. Biochem Biophys Res Commun 291 85-90 Madden DR (2002) The structure and function of glutamate receptor ion channels. Nat Rev Neurosci 3 91-101... 

S.J. Setford, R.M. Van Es, Y.J. Blankwater and S. Kroger, Receptor binding protein amperometric affinity sensor for rapid /Mactam quantification in milk, Anal. Chim. Acta, 398 (1999) 13-22. 

Cellular localization of growth hormone receptors/binding protein... 

Turnbull, A.V. and Rivier, C. 1997. Corticotropin-releasing factor (CRF) and endocrine responses to stress CRF receptors, binding protein, and related peptides. Proc Soc Exp Biol Med 215 1. 

As mentioned in Section 17.2.1, HA is a spike glycoprotein anchored to the virus lipid membrane [50], This glycoprotein functions as a receptor-binding protein and is responsible for the first step of viral infection when it binds to sialic acid residues of receptor glycoproteins on host cells [18]. When the virus is endocytosed into the cell, the low pH (5-6) changes the structure of HA, and this new fusion-active state triggers the fusion of the viral membrane and the endosome membrane, ultimately allowing entry of the viral nucleocapsid into the cytosol of the host cell [18]. 

An amphiphilic chemical messenger diffuses across the plasma membrane. Inside the cell the messenger molecules interact with specific receptors (binding proteins). In the ligand-bound state these receptors regulate the transcription of specific messenger RNAs and thereby control the expression of key enzymes, receptors or transporters. 

Dracheva S, McGurk SR, Haroutunian V. 2005. mRNA expression of AMPA receptors and AMPA receptor binding proteins in the cerebral cortex of elderly schizophrenics. J Neurosci Res 79 868-878. 

Srivastava S, Ziff EB. 1999. ABP A novel AMPA receptor binding protein. Ann N YAcad Sci 868 561-564. 

Y5. Yan, S. D., Schmidt, A. M., Anderson, G. M., Zhang, J., Brett, J., et al Enhanced cellular oxidant stress by the interaction of advanced glycation end products with their receptors/binding proteins. J. Biol. Chem. 269, 9889-9897 (1994). 

Crk, She, Grb2 (growth-factor-receptor-binding protein), and IRSl (insulin receptor substrate ) have related functions. 

Ando, H., Mizutani, A., Matsu-ura, T. and Mikoshiba, K. (2003) IRBIT, a novel inositol 1,4,5-trisphosphate (1P3) receptor-binding protein, is released from the 1P3 receptorupon 1P3 binding to the receptor. J. Biol. Chem. 278, 10602-10612. 

Srivastava S, Osten P, Vilim FS, Khatri L, Inman G, States B, Daly C, DeSouza S, Abagyan R, Valtschanoff JG, Weinberg RJ, Ziff EB (1998) Novel anchorage of GluR2/3 to the postsynaptic density by the AMPA receptor-binding protein ABP. Nemon 21 581-591. 

In addition to the three main types of immunological products that are widely available, more specialized preparations include synthetic peptide immune response modifiers such as those used to block T-cell responses in multiple sclerosis labelled monoclonal antibodies for cancer therapy or diagnosis and hybrid toxins containing a bacterial or plant toxin subunit attached to an antibody or human cell receptor-binding protein, and also intended mainly for cancer therapy. These have rather limited applications and for the most part, are designed to suppress or exploit the specificity of immune responses rather than to stimulate them. 

---