The Role of mRNA Localization in Membrane Protein Trafficking Specificity

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.

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Versatile role of the yeast ubiquitin ligase Rsp5p in intracellular trafficking

Biochemical Society Transactions ◽

10.1042/bst0360791 ◽

2008 ◽

Vol 36 (5) ◽

pp. 791-796 ◽

Cited By ~ 78

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.

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

The FASEB Journal ◽

10.1096/fasebj.24.1_supplement.506.1 ◽

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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A rapid and affordable screening platform for membrane protein trafficking

BMC Biology ◽

10.1186/s12915-015-0216-3 ◽

2015 ◽

Vol 13 (1) ◽

Cited By ~ 17

Author(s):

Joshua C. Snyder ◽

Thomas F. Pack ◽

Lauren K. Rochelle ◽

Subhasish K. Chakraborty ◽

Ming Zhang ◽

...

Keyword(s):

Membrane Protein ◽

Protein Trafficking ◽

Membrane Protein Trafficking ◽

Screening Platform

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Ethanol and Membrane Protein Trafficking: Diverse Mechanisms of Ethanol Action

Alcoholism Clinical and Experimental Research ◽

10.1111/j.1530-0277.2002.tb02536.x ◽

2002 ◽

Vol 26 (2) ◽

pp. 287-293 ◽

Cited By ~ 10

Author(s):

Laura E. Nagy ◽

M. Raj Lakshman ◽

Carol A. Casey ◽

Cynthia F. Bearer

Keyword(s):

Membrane Protein ◽

Protein Trafficking ◽

Membrane Protein Trafficking

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Kv2.1 cell surface clusters are insertion platforms for ion channel delivery to the plasma membrane

Molecular Biology of the Cell ◽

10.1091/mbc.e12-01-0047 ◽

2012 ◽

Vol 23 (15) ◽

pp. 2917-2929 ◽

Cited By ~ 55

Author(s):

Emily Deutsch ◽

Aubrey V. Weigel ◽

Elizabeth J. Akin ◽

Phil Fox ◽

Gentry Hansen ◽

...

Keyword(s):

Membrane Protein ◽

Cell Surface ◽

Ion Channel ◽

Protein Trafficking ◽

Hippocampal Neurons ◽

Surface Membrane ◽

Cell Types ◽

Homogeneous Surface ◽

Hek Cells ◽

Membrane Protein Trafficking

Voltage-gated K+ (Kv) channels regulate membrane potential in many cell types. Although the channel surface density and location must be well controlled, little is known about Kv channel delivery and retrieval on the cell surface. The Kv2.1 channel localizes to micron-sized clusters in neurons and transfected human embryonic kidney (HEK) cells, where it is nonconducting. Because Kv2.1 is postulated to be involved in soluble N-ethylmaleimide–sensitive factor attachment protein receptor–mediated membrane fusion, we examined the hypothesis that these surface clusters are specialized platforms involved in membrane protein trafficking. Total internal reflection–based fluorescence recovery after photobleaching studies and quantum dot imaging of single Kv2.1 channels revealed that Kv2.1-containing vesicles deliver cargo at the Kv2.1 surface clusters in both transfected HEK cells and hippocampal neurons. More than 85% of cytoplasmic and recycling Kv2.1 channels was delivered to the cell surface at the cluster perimeter in both cell types. At least 85% of recycling Kv1.4, which, unlike Kv2.1, has a homogeneous surface distribution, is also delivered here. Actin depolymerization resulted in Kv2.1 exocytosis at cluster-free surface membrane. These results indicate that one nonconducting function of Kv2.1 is to form microdomains involved in membrane protein trafficking. This study is the first to identify stable cell surface platforms involved in ion channel trafficking.

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