scholarly journals Uni-directional ciliary membrane protein trafficking by a cytoplasmic retrograde IFT motor and ciliary ectosome shedding

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Muqing Cao ◽  
Jue Ning ◽  
Carmen I Hernandez-Lara ◽  
Olivier Belzile ◽  
Qian Wang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Protein Trafficking ◽  
Protein Composition ◽  
Cytoplasmic Dynein ◽  
Cytoplasmic Microtubule ◽  
Dynamic Regulation ◽  
Ciliary Membrane ◽  
Membrane Protein Trafficking

The role of the primary cilium in key signaling pathways depends on dynamic regulation of ciliary membrane protein composition, yet we know little about the motors or membrane events that regulate ciliary membrane protein trafficking in existing organelles. Recently, we showed that cilium-generated signaling in Chlamydomonas induced rapid, anterograde IFT-independent, cytoplasmic microtubule-dependent redistribution of the membrane polypeptide, SAG1-C65, from the plasma membrane to the periciliary region and the ciliary membrane. Here, we report that the retrograde IFT motor, cytoplasmic dynein 1b, is required in the cytoplasm for this rapid redistribution. Furthermore, signaling-induced trafficking of SAG1-C65 into cilia is unidirectional and the entire complement of cellular SAG1-C65 is shed during signaling and can be recovered in the form of ciliary ectosomes that retain signal-inducing activity. Thus, during signaling, cells regulate ciliary membrane protein composition through cytoplasmic action of the retrograde IFT motor and shedding of ciliary ectosomes.

Versatile role of the yeast ubiquitin ligase Rsp5p in intracellular trafficking

2008 ◽  
Vol 36 (5) ◽  
pp. 791-796 ◽  
Author(s):  
Naima Belgareh-Touzé ◽  
Sébastien Léon ◽  
Zoi Erpapazoglou ◽  
Marta Stawiecka-Mirota ◽  
Danièle Urban-Grimal ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Ubiquitin Ligase ◽  
Protein Trafficking ◽  
Adaptor Proteins ◽  
Binding Domains ◽  
Independent Functions ◽  
Membrane Protein Trafficking ◽  
Ubiquitin Ligase E3

The ubiquitin ligase (E3) Rsp5p is the only member of the Nedd (neural-precursor-cell-expressed, developmentally down-regulated) 4 family of E3s present in yeast. Rsp5p has several proteasome-independent functions in membrane protein trafficking, including a role in the ubiquitination of most plasma membrane proteins, leading to their endocytosis. Rsp5p is also required for the ubiquitination of endosomal proteins, leading to their sorting to the internal vesicles of MVBs (multivesicular bodies). Rsp5p catalyses the attachment of non-conventional ubiquitin chains, linked through ubiquitin Lys-63, to some endocytic and MVB cargoes. This modification appears to be required for efficient sorting, possibly because these chains have a greater affinity for the ubiquitin-binding domains present within endocytic or MVB sorting complexes. The mechanisms involved in the recognition of plasma membrane and MVB substrates by Rsp5p remain unclear. A subset of Rsp5/Nedd4 substrates have a ‘PY motif’ and are recognized directly by the WW (Trp-Trp) domains of Rsp5p. Most Rsp5p substrates do not carry PY motifs, but some may depend on PY-containing proteins for their ubiquitination by Rsp5p, consistent with the latter's acting as specificity factors or adaptors. As in other ubiquitin-conjugating systems, these adaptors are also Rsp5p substrates and undergo ubiquitin-dependent trafficking. In the present review, we discuss recent examples illustrating the role of Rsp5p in membrane protein trafficking and providing new insights into the regulation of this E3 by adaptor proteins.

scholarly journals Regulation of ciliary membrane protein trafficking and signalling by kinesin motor proteins

FEBS Journal ◽  
2018 ◽  
Vol 285 (24) ◽  
pp. 4535-4564 ◽  
Author(s):  
Stine Kjær Morthorst ◽  
Søren Tvorup Christensen ◽  
Lotte Bang Pedersen
Keyword(s):  
Membrane Protein ◽  
Protein Trafficking ◽  
Motor Proteins ◽  
Kinesin Motor ◽  
Ciliary Membrane ◽  
Membrane Protein Trafficking ◽  
Kinesin Motor Proteins

scholarly journals BLOC-1 is required for selective membrane protein trafficking from endosomes to primary cilia

2017 ◽  
Vol 216 (7) ◽  
pp. 2131-2150 ◽  
Author(s):  
William J. Monis ◽  
Victor Faundez ◽  
Gregory J. Pazour
Keyword(s):  
Protein Trafficking ◽  
Primary Cilia ◽  
Recycling Endosome ◽  
Ciliary Membrane ◽  
Membrane Protein Trafficking ◽  
Selective Membrane ◽  
Specific Proteins ◽  
Lysosome Related Organelles ◽  
Extracellular Environment

Primary cilia perceive the extracellular environment through receptors localized in the ciliary membrane, but mechanisms directing specific proteins to this domain are poorly understood. To address this question, we knocked down proteins potentially important for ciliary membrane targeting and determined how this affects the ciliary trafficking of fibrocystin, polycystin-2, and smoothened. Our analysis showed that fibrocystin and polycystin-2 are dependent on IFT20, GMAP210, and the exocyst complex, while smoothened delivery is largely independent of these components. In addition, we found that polycystin-2, but not smoothened or fibrocystin, requires the biogenesis of lysosome-related organelles complex-1 (BLOC-1) for ciliary delivery. Consistent with the role of BLOC-1 in sorting from the endosome, we find that disrupting the recycling endosome reduces ciliary polycystin-2 and causes its accumulation in the recycling endosome. This is the first demonstration of a role for BLOC-1 in ciliary assembly and highlights the complexity of pathways taken to the cilium.

scholarly journals In search for an appropriate model to study the role of MYO5B in apical membrane protein trafficking

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Katarina Mackovicova ◽  
Annemieke T Goot ◽  
Klaas A Sjollema ◽  
Ellen AA Nollen ◽  
Sven CD Ijzendoorn
Keyword(s):  
Membrane Protein ◽  
Protein Trafficking ◽  
Apical Membrane ◽  
Membrane Protein Trafficking
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