Blog
About

252
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Direct recording and molecular identification of the calcium channel of primary cilia

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Summary

          A primary cilium is a solitary slender non-motile protuberance of structured microtubules (9+0) enclosed by plasma membrane 1 . Housing components of the cell division apparatus between cell divisions, they also serve as specialized compartments for calcium signaling 2 and Hedgehog (Hh) signaling pathways 3 . Specialized sensory cilia such as retinal photoreceptors and olfactory cilia employ diverse ion channels 4- 7 . An ion current has been measured from primary cilia of kidney cells 8 but the responsible genes have not been identified. The polycystin proteins (PC, PKD), identified in linkage studies of polycystic kidney disease 9 , are candidate channels divided into two structural classes: 11-transmembrane (TM) proteins (PKD1, PKD1-L1 and PKD1-L2) remarkable for a large extracellular N-terminus of putative cell adhesion domains and a GPCR proteolytic site, and the 6-TM channel proteins (PKD2, PKD2-L1, PKD2-L2; TRPPs). Evidence suggests that the PKD1s associate with the PKD2s via coiled-coil domains 10- 12 . Here, we employ a transgenic mouse in which only cilia express a fluorophore and employ it to directly record from primary cilia and demonstrate that PKD1-L1 and PKD2-L1 form ion channels at high densities in several cell types. In conjunction with the companion manuscript 2 , we show that the PKD1-L1/PKD2-L1 heteromeric channel establishes the cilia as a unique calcium compartment within cells that modulates established Hedgehog pathways.

          Related collections

          Most cited references 30

          • Record: found
          • Abstract: found
          • Article: not found

          Vertebrate Smoothened functions at the primary cilium.

          The unanticipated involvement of several intraflagellar transport proteins in the mammalian Hedgehog (Hh) pathway has hinted at a functional connection between cilia and Hh signal transduction. Here we show that mammalian Smoothened (Smo), a seven-transmembrane protein essential for Hh signalling, is expressed on the primary cilium. This ciliary expression is regulated by Hh pathway activity; Sonic hedgehog or activating mutations in Smo promote ciliary localization, whereas the Smo antagonist cyclopamine inhibits ciliary localization. The translocation of Smo to primary cilia depends upon a conserved hydrophobic and basic residue sequence homologous to a domain previously shown to be required for the ciliary localization of seven-transmembrane proteins in Caenorhabditis elegans. Mutation of this domain not only prevents ciliary localization but also eliminates Smo activity both in cultured cells and in zebrafish embryos. Thus, Hh-dependent translocation to cilia is essential for Smo activity, suggesting that Smo acts at the primary cilium.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            ANKTM1, a TRP-like channel expressed in nociceptive neurons, is activated by cold temperatures.

            Mammals detect temperature with specialized neurons in the peripheral nervous system. Four TRPV-class channels have been implicated in sensing heat, and one TRPM-class channel in sensing cold. The combined range of temperatures that activate these channels covers a majority of the relevant physiological spectrum sensed by most mammals, with a significant gap in the noxious cold range. Here, we describe the characterization of ANKTM1, a cold-activated channel with a lower activation temperature compared to the cold and menthol receptor, TRPM8. ANKTM1 is a distant family member of TRP channels with very little amino acid similarity to TRPM8. It is found in a subset of nociceptive sensory neurons where it is coexpressed with TRPV1/VR1 (the capsaicin/heat receptor) but not TRPM8. Consistent with the expression of ANKTM1, we identify noxious cold-sensitive sensory neurons that also respond to capsaicin but not to menthol.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Piezos are pore-forming subunits of mechanically activated channels

              Mechanotransduction plays a crucial role in physiology. Biological processes including sensing touch and sound waves require yet unidentified cation channels that detect pressure. Mouse piezo1 (mpiezo1) and mpiezo2 induce mechanically activated cationic currents in cells; however, it is unknown if piezos are pore-forming ion channels or modulate ion channels. We show that Drosophila piezo (dpiezo) also induces mechanically activated currents in cells, but through channels with remarkably distinct pore properties including sensitivity to the pore blocker ruthenium red and single channel conductances. mpiezo1 assembles as a ~1.2 million-Dalton tetramer, with no evidence of other proteins in this complex. Finally, purified mpiezo1 reconstituted into asymmetric lipid bilayers and liposomes forms ruthenium red-sensitive ion channels. These data demonstrate that piezos are an evolutionarily conserved ion channel family involved in mechanotransduction.
                Bookmark

                Author and article information

                Journal
                0410462
                6011
                Nature
                Nature
                Nature
                0028-0836
                1476-4687
                5 May 2014
                12 December 2013
                27 June 2014
                : 504
                : 7479
                : 315-318
                Affiliations
                [1 ]Howard Hughes Medical Institute, Department of Cardiology, Children's Hospital Boston, 320 Longwood Avenue, Boston, MA 02115, USA
                [2 ]Department of Neuroscience, School of Medicine, Tufts University, Boston, MA 02111, USA
                [3 ]Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
                Author notes
                []Correspondence and requests for materials should be addressed to D.E.C. ( dclapham@ 123456enders.tch.harvard.edu )
                [*]

                These authors contributed equally to this work

                HHMIMS539239
                10.1038/nature12832
                4073646
                24336289

                Users may view, print, copy, download and text and data- mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: http://www.nature.com/authors/editorial_policies/license.html#terms

                Categories
                Article

                Uncategorized

                Comments

                Comment on this article