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. Author manuscript; available in PMC: 2016 Feb 29.
Published in final edited form as: Adv Immunol. 2015 Feb 7;126:45–127. doi: 10.1016/bs.ai.2014.11.002

Figure 1. The effect of various gene knockouts on the storage of mast cell (MC) granule compounds.

Figure 1

The figure depicts the granule contents of MCs from wild-type mice of C57BL/6 genetic background. MC granules can contain several preformed compounds, including serglycin proteoglycan, chymases (mMCP-1, mMCP-2, mMCP-4, mMCP-5), tryptases (mMCP-6; mMCP-7 is absent in C57BL/6 mice), CPA3, bioactive amines (histamine, serotonin), various lysosomal hydrolases (such as β-hexosaminidase), and certain cytokines. For simplicity, a hypothetical granule of mixed “CTMC” (expressing mMCP-4, mMCP-5, mMCP-6, CPA3)/“MMC” (expressing mMCP-1, mMCP-2) phenotype is shown. As indicated, many of the granule compounds are stored in complex with serglycin proteoglycan and the absence of serglycin results in impaired storage of such compounds. However, note that several granule constituents (such as mMCP-1) are stored independently of serglycin, whereas others (such as mMCP-2) depend only partially on serglycin for storage. It is not yet established whether any cytokines which can be found in granules depend on serglycin for storage (indicated by “?” in the figure). Note that the absence of CPA3 leads to a secondary defect in the storage of mMCP-5 and vice versa; that is, the absence of mMCP-5 results in impaired CPA3 storage. In contrast, the absence of mMCP-4 or mMCP-6 does not induce pronounced effects on the storage of other granule mediators.