Extended cleavage specificities of mast cell proteases 1 and 2 from golden hamster: Classical chymase and an elastolytic protease comparable to rat and mouse MCP-5.

Lawrence De Garavilla,Zhirong Fu,Jukka Kervinen,Lars Hellman,Michael Thorpe,Emanuelle Albat,Srinivas Akula

doi:10.1371/journal.pone.0207826

Lawrence De Garavilla, Zhirong Fu + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0207826

Copy DOI

Abstract

Serine proteases constitute the major protein content of mast cell secretory granules. Here we present the extended cleavage specificity of two such proteases from the golden hamster, Mesocricetus auratus. Analysis by phage display technique showed that one of them (HAM1) is a classical chymase with a specificity similar to the human mast cell chymase. However, in contrast to the human chymase, it does not seem to have a particular preference for any of the three aromatic amino acids, Phe, Tyr and Trp, in the P1 position of substrates. HAM1 also efficiently cleaved after Leu similarly to human and many other mast cell chymases. We observed only a 3-fold lower cleavage activity on Leu compared to substrates with P1 aromatic amino acids. Chymotryptic enzymes seem to be characteristic for connective tissue mast cells in mammalian species from opossums to humans, which indicates a very central role of these enzymes in mast cell biology. HAM1 also seems to have the strongest preference for negatively charged amino acids in the P2´position of all mast cell chymases so far characterized. The second hamster chymase, HAM2, is an elastolytic in its activity, similarly to the α-chymases in rats and mice (rMCP-5 and mMCP-5, respectively). The presence of an α-chymase that developed elastase activity thereby seems to be a relatively early modification of the α-chymase within the rodent branch of the mammalian evolutionary tree.

Highlights

Mast cells (MCs) are resident tissue cells frequently found in the connective tissue of the skin and around blood vessels and nerves as well as in the mucosa of the airways and intestines
Our results confirmed that the hamster α-chymase (HAM2) is an elastase, thereby indicating an early change in specificity in the rodent branch of the mammalian evolutionary tree, and that one β-chymase has taken a role as the primary chymotryptic enzyme
The analysis of hamster chymase 1 (HAM1) confirmed the finding from the phage display analysis that this protease had a relatively strong preference for negatively charged amino acids in the P2’ position, similar to what has been observed for many other mammalian mast cell chymases including the human chymase and mouse mast cell protease (mMCP)-4 (Fig 8C) [19]

Summary

Introduction

Mast cells (MCs) are resident tissue cells frequently found in the connective tissue of the skin and around blood vessels and nerves as well as in the mucosa of the airways and intestines. Our results confirmed that the hamster α-chymase (HAM2) is an elastase, thereby indicating an early change in specificity in the rodent branch of the mammalian evolutionary tree, and that one β-chymase has taken a role as the primary chymotryptic enzyme. This hamster enzyme (HAM1) is the mammalian chymase with the strongest P2 ́preference for negatively charged amino acids. Based on the phylogenetic tree (Fig 1) we conclude that the golden hamster and the Chinese hamster both have mMCP-8 related genes, indicating that these enzymes appeared early in rodents This gene has not been found in any other mammalian species except rodents, indicating rodent-specific functions for both the mMCP-8 related proteases as well as elastase specific α-chymases

Results

Discussion

Experimental procedures Phylogenetic tree and sequence alignments