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. Author manuscript; available in PMC: 2022 Dec 1.
Published in final edited form as: Ann Allergy Asthma Immunol. 2021 Aug 13;127(6):638–647. doi: 10.1016/j.anai.2021.08.009

Figure 2. Putative effects of mature tryptases in HαT.

Figure 2.

Increased TPSAB1 copy number encoding α-tryptase is associated with generation of mature αβ-tryptase heterotetramers. Following mast cell activation and release of secretory granule contents, mature αβ-tryptases can contribute to mast cell degranulation in an autocrine manner through cleavage of the mechanoreceptor EMR2. αβ-Tryptases also selectively cleave and activate PAR2, potentially leading to increased acute vascular permeability and neuroinflammation. Mature β-tryptases have been shown to promote proliferation of connective tissue fibroblasts and airway smooth muscle cells which is associated with extracellular matrix remodeling and fibrosis. In the airways, mature β-tryptases have also been shown to promote smooth muscle tone, potentially in part by cleaving the bronchodilator VIP. *It is currently unknown whether αβ-tryptases have differential effects on connective tissue and airway phenotypes. EMR2, EGF-Like Module-Containing Mucin-Like Hormone Receptor-Like 2; PAR2, protease-activated receptor 2; VIP, vasoactive intestinal peptide; MRGPRX2, Mas-related G protein-coupled receptor-X2; FcεRI, high affinity IgE receptor.