9daz

Structural highlights

Function

AMPN_FELCA Broad specificity aminopeptidase which plays a role in the final digestion of peptides generated from hydrolysis of proteins by gastric and pancreatic proteases. Also involved in the processing of various peptides including peptide hormones, such as angiotensin III and IV, neuropeptides, and chemokines. May also be involved the cleavage of peptides bound to major histocompatibility complex class II molecules of antigen presenting cells. May have a role in angiogenesis and promote cholesterol crystallization. May have a role in amino acid transport by acting as binding partner of amino acid transporter SLC6A19 and regulating its activity (By similarity).[UniProtKB:P15144][UniProtKB:P97449] (Microbial infection) In case of feline coronavirus (FCoV) infection, serves as a receptor for FCoV spike glycoprotein. It is as well a receptor for other serogroup I coronaviruses, like canine coronavirus (CCoV), porcine transmissible gastroenteritis virus (TGEV), and human coronavirus 229E (HCoV-229E). Also serves as a receptor for infectious bronchitis virus (IBV, Arkansas 99 serotype) in serogroup III.^{[1] [2] [3]} IGG1_HUMAN Immunoglobulins, also known as antibodies, are membrane-bound or secreted glycoproteins produced by B lymphocytes. In the recognition phase of humoral immunity, the membrane-bound immunoglobulins serve as receptors which, upon binding of a specific antigen, trigger the clonal expansion and differentiation of B lymphocytes into immunoglobulins-secreting plasma cells. Secreted immunoglobulins mediate the effector phase of humoral immunity, which results in the elimination of bound antigens (PubMed:22158414, PubMed:20176268). The antigen binding site is formed by the variable domain of one heavy chain, together with that of its associated light chain. Thus, each immunoglobulin has two antigen binding sites with remarkable affinity for a particular antigen. The variable domains are assembled by a process called V-(D)-J rearrangement and can then be subjected to somatic hypermutations which, after exposure to antigen and selection, allow affinity maturation for a particular antigen (PubMed:20176268, PubMed:17576170).^{[4] [5] [6]}

References

1. ↑ Miguel B, Pharr GT, Wang C. The role of feline aminopeptidase N as a receptor for infectious bronchitis virus. Brief review. Arch Virol. 2002 Nov;147(11):2047-56. PMID:12417943 doi:10.1007/s00705-002-0888-1
2. ↑ Tresnan DB, Levis R, Holmes KV. Feline aminopeptidase N serves as a receptor for feline, canine, porcine, and human coronaviruses in serogroup I. J Virol. 1996 Dec;70(12):8669-74. PMID:8970993 doi:10.1128/JVI.70.12.8669-8674.1996
3. ↑ Hegyi A, Kolb AF. Characterization of determinants involved in the feline infectious peritonitis virus receptor function of feline aminopeptidase N. J Gen Virol. 1998 Jun;79 ( Pt 6):1387-91. PMID:9634079
4. ↑ Teng G, Papavasiliou FN. Immunoglobulin somatic hypermutation. Annu Rev Genet. 2007;41:107-20. PMID:17576170 doi:http://dx.doi.org/10.1146/annurev.genet.41.110306.130340
5. ↑ Schroeder HW Jr, Cavacini L. Structure and function of immunoglobulins. J Allergy Clin Immunol. 2010 Feb;125(2 Suppl 2):S41-52. doi:, 10.1016/j.jaci.2009.09.046. PMID:20176268 doi:http://dx.doi.org/10.1016/j.jaci.2009.09.046
6. ↑ McHeyzer-Williams M, Okitsu S, Wang N, McHeyzer-Williams L. Molecular programming of B cell memory. Nat Rev Immunol. 2011 Dec 9;12(1):24-34. doi: 10.1038/nri3128. PMID:22158414 doi:http://dx.doi.org/10.1038/nri3128