The Activity of Hyaluronan Synthase 2 Is Regulated by Dimerization and Ubiquitination |
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| Authors: | Eugenia Karousou Masaru Kamiryo Spyros S. Skandalis Aino Ruusala Trias Asteriou Alberto Passi Hidetoshi Yamashita Ulf Hellman Carl-Henrik Heldin Paraskevi Heldin |
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| Affiliation: | From the ‡Ludwig Institute for Cancer Research, Uppsala University Biomedical Center, SE-75124 Uppsala, Sweden.;§DSBSC, University of Insubria, via Dunant 5, 21100 Varese, Italy, and ;the ¶Department of Ophthalmology and Visual Science, Yamagata University School of Medicine, 2-2-2 lidanishi, Yamagata 990-9585, Japan |
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| Abstract: | Hyaluronan is a component of the extracellular matrix, which affects tissue homeostasis. In this study, we investigated the regulatory mechanisms of one of the hyaluronan-synthesizing enzymes, HAS2. Ectopic expression of Flag- and 6myc-HAS2 in COS-1 cells followed by immunoprecipitation and immunoblotting revealed homodimers; after co-transfection with Flag-HAS3, also heterodimers were seen. Furthermore, the expressed HAS2 was ubiquitinated. We identified one acceptor site for ubiquitin on lysine residue 190. Mutation of this residue led to inactivation of the enzymatic activity of HAS2. Interestingly, K190R-mutated HAS2 formed dimers with wt HAS2 and quenched the activity of wt HAS2, thus demonstrating a functional role of the dimeric configuration. |
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| Keywords: | Glycosaminoglycan Hyaluronate Mass Spectrometry (MS) Protein Motifs Protein Stability Ubiquitin |
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