The transition zone protein Rpgrip1l regulates proteasomal activity at the primary cilium.
Bottom Line: Mutations in RPGRIP1L result in severe human diseases called ciliopathies.Indeed, we detected a cilia-dependent decreased proteasomal activity in the absence of Rpgrip1l.We found different proteasomal components localized to cilia and identified Psmd2, a component of the regulatory proteasomal 19S subunit, as an interaction partner for Rpgrip1l.
Affiliation: Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany Christoph.Gerhardt@hhu.de.Show MeSH
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Mentions: Originally, Rpgrip1l has been shown to be a BB protein (Arts et al., 2007; Delous et al., 2007; Vierkotten et al., 2007). More recent reports describe a more detailed localization at the ciliary TZ (Garcia-Gonzalo et al., 2011; Williams et al., 2011; Mahuzier et al., 2012). We choose mouse embryonic fibroblasts (MEFs) as in vitro system for analyzing Rpgrip1l function. In these primary cells, Rpgrip1l is located at the TZ during G0 phase (Fig. 1, A and B) and at both centrosomes during mitosis (Fig. 1 C). In embryonic day 12.5 (E12.5) limb cilia, Rpgrip1l is also present at the TZ and at centrosomes (Fig. 1 D). This means that in vivo studies of limbs, a well-known system for studying functional mechanisms, can be used to complement the data of MEFs.
Affiliation: Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany Christoph.Gerhardt@hhu.de.