tailieunhanh - Báo cáo khoa học: A role for serglycin proteoglycan in granular retention and processing of mast cell secretory granule components

In the absence of serglycin proteoglycans, connective tissue-type mast cells fail to assemble mature metachromatic secretory granules, and this is accompanied by a markedly reduced ability to store neutral proteases. However, the mechanisms behind these phenomena are not known. | ỊFEBS Journal A role for serglycin proteoglycan in granular retention and processing of mast cell secretory granule components Frida Henningsson Sonja Hergeth Robert Cortelius Magnus Abrink and Gunnar Pejler Swedish University of AgriculturalSciences Department of Molecular Biosciences The BiomedicalCenter Uppsala Sweden Keywords mast cells proteases proteoglycans serglycin sorting Correspondence G. Pejler Swedish University of Agricultural Sciences Department of Molecular Biosciences The BiomedicalCenter Box 575 751 23 Uppsala Sweden Fax 46 18 550762 Tel 46 18 4714090 E-mail These authors contributed equally to this work Received 28 June 2006 revised 15 August 2006 accepted 4 September 2006 doi In the absence of serglycin proteoglycans connective tissue-type mast cells fail to assemble mature metachromatic secretory granules and this is accompanied by a markedly reduced ability to store neutral proteases. However the mechanisms behind these phenomena are not known. In this study we addressed these issues by studying the functionality and morphology of secretory granules as well as the fate of the secretory granule proteases in bone marrow-derived mast cells from serglycin 7 and serglycin7 mice. We show that functional secretory vesicles are formed in both the presence and absence of serglycin but that dense core formation is defective in serglycin7 mast cell granules. The low levels of mast cell proteases present in serglycin7 cells had a granular location as judged by immunohistochemistry and were released following exposure to calcium ionophore indicating that they were correctly targeted into secretory granules even in the absence of serglycin. In the absence of serglycin the fates of the serglycin-dependent proteases differed including preferential degradation exocytosis or defective intracellular processing. In contrast b-hexosa-minidase storage and release was not dependent on serglycin. Together these