From the cytoplasm into the cilium: bon voyage.
The primary cilium compartmentalizes a tiny fraction of the cell surface and volume, yet many proteins are highly enriched in this area and so efficient mechanisms are necessary to concentrate them in the ciliary compartment. Here we review mechanisms that are thought to deliver protein cargo to the base of cilia and are likely to interact with ciliary gating mechanisms. Given the immense variety of ciliary cytosolic and transmembrane proteins, it is almost certain that multiple, albeit frequently interconnected, pathways mediate this process. It is also clear that none of these pathways is fully understood at the present time. Mechanisms that are discussed below facilitate ciliary localization of structural and signaling molecules, which include receptors, G-proteins, ion channels, and enzymes. These mechanisms form a basis for every aspect of cilia function in early embryonic patterning, organ morphogenesis, sensory perception and elsewhere.
MRC Centre for Developmental and Biomedical Genetics; Department of Biomedical Science; The University of Sheffield; Sheffield, UK.
Jarema
J
Malicki
University of Toledo; Department of Biological Sciences; Toledo, OH USA.
Tomer
T
Avidor-Reiss
D001692:Biological Transport; D002502:Centrioles / Q000378:metabolism; D002923:Cilia / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D058112:Septins / Q000378:metabolism
D058112:Septins
compartment; diffusion barrier; membrane; receptor; signal transduction; signaling; transport