Mast Cell α and β Tryptases Changed Rapidly during Primate Speciation and Evolved from γ-Like Transmembrane Peptidases in Ancestral Vertebrates This information is current as of September 25, 2021. Neil N. Trivedi, Qiao Tong, Kavita Raman, Vikash J. Bhagwandin and George H. Caughey J Immunol 2007; 179:6072-6079; ; doi: 10.4049/jimmunol.179.9.6072 http://www.jimmunol.org/content/179/9/6072 Downloaded from References This article cites 34 articles, 15 of which you can access for free at: http://www.jimmunol.org/content/179/9/6072.full#ref-list-1 http://www.jimmunol.org/ Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication by guest on September 25, 2021 *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2007 by The American Association of Immunologists All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Mast Cell ␣ and ␤ Tryptases Changed Rapidly during Primate Speciation and Evolved from ␥-Like Transmembrane Peptidases in Ancestral Vertebrates1 Neil N. Trivedi, Qiao Tong, Kavita Raman, Vikash J. Bhagwandin, and George H. Caughey2 Human mast cell tryptases vary strikingly in secretion, catalytic competence, and inheritance. To explore the basis of variation, we compared genes from a range of primates, including humans, great apes (chimpanzee, gorilla, orangutan), Old- and New- World monkeys (macaque and marmoset), and a prosimian (galago), tracking key changes. Our analysis reveals that extant soluble tryptase-like proteins, including ␣- and ␤-like tryptases, mastins, and implantation serine proteases, likely evolved from membrane-anchored ancestors because their more deeply rooted relatives (␥ tryptases, pancreasins, prostasins) are type I trans- membrane peptidases. Function-altering mutations appeared at widely separated times during primate speciation, with tryptases Downloaded from evolving by duplication, gene conversion, and point mutation. The ␣-tryptase Gly216Asp catalytic domain mutation, which di- minishes activity, is present in macaque tryptases, and thus arose before great apes and Old World monkeys shared an ancestor, ,and before the ␣␤ split. However, the Arg؊3Gln processing mutation appeared recently, affecting only human ␣. By comparison the transmembrane ␥-tryptase gene, which anchors the telomeric end of the multigene tryptase locus, changed little during primate evolution. Related transmembrane peptidase genes were found in reptiles, amphibians, and fish. We identified soluble tryptase-like genes in the full spectrum of mammals, including marsupial (opossum) and monotreme (platypus), but not in http://www.jimmunol.org/ nonmammalian vertebrates. Overall, our analysis suggests that soluble tryptases evolved rapidly from membrane-anchored, two-chain peptidases in ancestral vertebrates into soluble, single-chain, self-compartmentalizing, inhibitor-resistant oligomers expressed primarily by mast cells, and that much of present numerical, behavioral, and genetic diversity of ␣- and ␤-like tryptases was acquired during primate evolution. The Journal of Immunology, 2007, 179: 6072–6079. uman mast cell tryptases exhibit impressively diverse apparent failure of autocatalytic maturation (9). Also, ␣ appears to processing, secretion, solubility, catalytic activity, and have a critical catalytic domain mutation, which greatly reduces inheritance. As a group, tryptases are implicated in al- activity toward substrates readily cleaved by ␤ tryptases. This mu- H by guest on September 25, 2021 lergic and other types of inflammation. All mast cell tryptase genes tation perturbs the active site in a manner that is unproductive for cluster tightly on chromosome 16p13.3 (1). Products of these substrate binding (10–12). In contrast to ␤ tryptase, ␣ fails to genes fall into two general categories: membrane-anchored and evoke neutrophilic inflammation (13) and most or all of it appears soluble. The ␥ gene, TPSG1, encodes a type I transmembrane pep- to be secreted (probably as a proenzyme) and not stored in mast tidase anchored to the cell surface after secretion (2, 3). Behavior cell granules (14). ␣ Genes are absent in a substantial portion of of peptidase chimeras containing part of mouse ␥ tryptase suggests most humans (6). This appears to be because they are alleles at a that the anchor is a C-terminal hydrophobic peptide, which is not locus that also accepts ␤I genes (1). Humans without ␣ genes have exchanged for a lipid anchor, as occurs in some related enzymes, diminished circulating levels of immunoreactive tryptase com- including prostasin (4). In humans, ␥ is the sole membrane-an- pared with those with ␣ genes (15). Thus, ␣ and ␤ tryptases differ chored tryptase and is hypothesized to be proinflammatory (5). The in important ways. other three transcribed tryptase genes encode soluble enzymes ␤ Tryptases are products of two adjacent loci. The major alleles lacking an anchor. These are TPSAB1 (encoding ␣ and ␤I trypta- (I–III) are highly similar (16, 17). ␤ Tryptases encode soluble, ses), TPSB2 (encoding ␤II and ␤III), and TPSD1 (encoding ␦ active enzymes that are stored in secretory granules and released in tryptases) (1, 6, 7). response to allergen-bound IgE and other stimuli (18). They self- ␣ Tryptase, the first human tryptase to have its full primary assemble into tetramers, which shield the active site from inacti- structure determined (8), features a propeptide mutation causing vation by circulating inhibitors (19). ␤ Tryptases are the dominant forms isolated from tissue extracts and are targets for therapeutic inhibition because of postulated importance in diseases such as Cardiovascular Research Institute and Department of Medicine, University of Cali- asthma, anaphylaxis, and inflammatory bowel disease (7, 20, 21). fornia, San Francisco, CA 94143; Northern California Institute for Research and ␦ Education, San Francisco, CA 94121; and Veterans Affairs Medical Center, San Fran- Human tryptases differ in that they are C-terminally truncated cisco, CA 94121 (1). They also feature the propeptide mutation that blocks process- Received for publication June 27, 2007. Accepted for publication August 10, 2007. ing in ␣ tryptases. Consequently, ␦ tryptase has little catalytic ac- The costs of publication of this article were defrayed in part by the payment of page tivity (22) and may have defective propeptide processing. Al- charges. This article must therefore be hereby marked advertisement in accordance though the ␦ gene TPSD1 was first hypothesized to be a with 18 U.S.C. Section 1734 solely to indicate this fact. pseudogene (1, 23), transcripts and immunoreactivity were later 1 This work was supported by National Institutes of Health Grant HL024136 and the detected in multiple organs (22). However, the targets and roles, if Northern California Institute for Research and Education. any, of ␦ tryptases remain to be determined. 2 Address correspondence and reprint requests to Dr. George H. Caughey, Veterans Affairs Medical Center, Mailstop 111D, 4150 Clement Street, San Francisco, CA The origins of human tryptase isoforms and of mammalian 94121. E-mail address: [email protected] tryptases in general are obscure. Unlike many other mammalian www.jimmunol.org The Journal of Immunology 6073 Table I. Primate tryptase sequences: nomenclature, sources, and identifiers Primate Protein GenBank Identifier Homo sapiens (human) Tryptase, ␣I, ␣II M30038; AF098328 Tryptase, ␤I M33494 Tryptase, ␤II M33492 and AF099145 Tryptase, ␤III AF099143 Tryptase, ␥I, ␥II NM_012467; AAF76458 Tryptase, ␦I NM_012217 ISP2 AF529082a Pan troglodytes (chimpanzee) Tryptase, ␣ XM_001158624 Tryptase, ␤ EF206351a Gorilla gorilla (gorilla) Tryptase, ␤1 EF208020a Tryptase, ␤2 EF208021a Tryptase, ␤3 EF208022a Pongo pygmaeus abelii (Sumatran orangutan) Tryptase, ␤1 EF452227a Tryptase, ␤2 EF452228a Tryptase, ␤3 EF452229a Tryptase, ␤4 EF452230a Macaca fascicularis (crab-eating macaque) Tryptase, ␣␤1 EF212445a Tryptase, ␣␤2 EF212444a Macaca mulatta (rhesus macaque) Tryptase, ␣␤ XM_001088289 Downloaded from Tryptase, ␥ AANU01106415b ISP2 XP_001118570 Callithrix jacchus (common marmoset) Tryptase Contig12371.9c Tryptase, ␥ Contig12371.8c Otolemur garnettii (small-eared galago) Tryptase, ␥ AAQR01303204b a Cloned and sequenced, this work. b Deduced from unannotated whole genome shotgun sequence. http://www.jimmunol.org/ c Deduced from unannotated sequences from http://blast.wustl.edu. peptidases, tryptases lack obvious orthologs in nonmammalian genomic DNA from species-specific cultured fibroblasts. DNA encoding vertebrates. To understand origins and consequences of the diver- primate ␣- and ␤-like genes was amplified by PCR using Advantage 2 (BD Clontech). For ␣- and ␤-like genes, primers bracketed full protein-coding sity of expressed human tryptases, the present study probes the Ј Ј ␣ ␤ ␥ sequence and were based on highly conserved portions of the 3 and 5 evolution of human , , and tryptases. The data acquired