Glycosylinositol phosphorylceramides from Rosa cell cultures are boron-bridged in the plasma membrane and form complexes with rhamnogalacturonan II.
Bottom Line: Using high-voltage paper electrophoresis, we showed that addition of GIPCs decreased the electrophoretic mobility of radiolabelled RG-II, suggesting formation of a GIPC-B-RG-II complex.We conclude that B plays a structural role in the plasma membrane.Finally, our results suggest a role for GIPCs in the RG-II dimerization process.
Affiliation: The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh, EH9 3JH, UK.Show MeSH
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Mentions: Results retrieved (Figure6) from Atted-II database (Obayashi et al., 2014) revealed that genes involved in GIPC biosynthesis, such as LAG ONE HOMOLOGUE (LOH) encoding a ceramide synthase (Ternes et al., 2011), were co-expressed in several species with genes involved in the biosynthesis of RG-II such as ketodeoxyoctulosonic acid [involved in biosynthesis of 3-deoxy-d-manno-2-octulosonic acid (KDO)] and RGXT (RG-II xylosyltransferase; involved in side-chain A biosynthesis). Likewise, LOH genes are co-expressed with genes involved in the biosynthesis of RG-II’s homogalacturonan backbone (GAUT1, GAUT7 and GAUT8, encoding three galacturonosyltransferases). Moreover, both RG-II and GIPC biosynthesis occur in the Golgi apparatus (Mohnen, 2008); therefore, if the B-dependent dimerization of RG-II does require the intermediacy of a GIPC–B–RG-II complex, all necessary participants in the process would be present together in the endo-membrane/exocytosis system – which is the major location of RG-II dimerization in vivo (Chormova et al., 2013).
Affiliation: The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, The University of Edinburgh, Edinburgh, EH9 3JH, UK.