Ciliary protein turnover continues in the presence of inhibitors of golgi function: Evidence for membrane protein pools and unconventional intracellular membrane dynamics

2001 ◽  
Vol 289 (6) ◽  
pp. 335-349 ◽  
Author(s):  
Raymond E. Stephens
Keyword(s):  
Membrane Protein ◽  
Protein Turnover ◽  
Membrane Dynamics ◽  
Intracellular Membrane ◽  
Ciliary Protein

scholarly journals A Novel Golgi Membrane Protein Is a Partner of the ARF Exchange Factors Gea1p and Gea2p

2003 ◽  
Vol 14 (6) ◽  
pp. 2357-2371 ◽  
Author(s):  
Sophie Chantalat ◽  
Rëgis Courbeyrette ◽  
Francesca Senic-Matuglia ◽  
Catherine L. Jackson ◽  
Bruno Goud ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Protein Trafficking ◽  
Transmembrane Domain ◽  
Integral Membrane Protein ◽  
Membrane Dynamics ◽  
General Interest ◽  
Single Mutation ◽  
Golgi Membrane ◽  
Nucleotide Exchange

The Sec7 domain guanine nucleotide exchange factors (GEFs) for the GTPase ARF are highly conserved regulators of membrane dynamics and protein trafficking. The interactions of large ARF GEFs with cellular membranes for localization and/or activation are likely to participate in regulated recruitment of ARF and effectors. However, these interactions remain largely unknown. Here we characterize Gmh1p, the first Golgi transmembrane-domain partner of any of the high-molecular-weight ARF-GEFs. Gmh1p is an evolutionarily conserved protein. We demonstrate molecular interaction between the yeast Gmh1p and the large ARF-GEFs Gea1p and Gea2p. This interaction involves a domain of Gea1p and Gea2p that is conserved in the eukaryotic orthologues of the Gea proteins. A single mutation in a conserved amino acid residue of this domain is sufficient to abrogate the interaction, whereas the overexpression of Gmh1p can compensate in vivo defects caused by mutations in this domain. We show that Gmh1p is an integral membrane protein that localizes to the early Golgi in yeast and in human HeLa cells and cycles through the ER. Hence, we propose that Gmh1p acts as a positive Golgi-membrane partner for Gea function. These results are of general interest given the evolutionary conservation of both ARF-GEFs and the Gmh proteins.

scholarly journals An intracellular membrane protein GEP1 regulates xanthurenic acid induced gametogenesis of malaria parasites

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuanyuan Jiang ◽  
Jun Wei ◽  
Huiting Cui ◽  
Chuanyuan Liu ◽  
Yuan Zhi ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Xanthurenic Acid ◽  
Intracellular Membrane ◽  
Malaria Parasites

scholarly journals The Na+ pump Ena1 is a yeast epsin-specific cargo requiring its ubiquitylation and phosphorylation sites for internalization

2020 ◽  
Vol 133 (16) ◽  
pp. jcs245415
Author(s):  
Arpita Sen ◽  
Wen-Chieh Hsieh ◽  
Claudia B. Hanna ◽  
Chuan-Chih Hsu ◽  
McKeith Pearson ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Protein Turnover ◽  
Spatial Organization ◽  
Protein Sorting ◽  
Cytoplasmic Tail ◽  
Phosphorylation Sites ◽  
Na Pump ◽  
Substantial Progress ◽  
Casein Kinases ◽  
Standing Question

ABSTRACTIt is well known that in addition to its classical role in protein turnover, ubiquitylation is required for a variety of membrane protein sorting events. However, and despite substantial progress in the field, a long-standing question remains: given that all ubiquitin units are identical, how do different elements of the sorting machinery recognize their specific cargoes? Our results indicate that the yeast Na+ pump Ena1 is an epsin (Ent1 and Ent2 in yeast)-specific cargo and that its internalization requires K1090, which likely undergoes Art3-dependent ubiquitylation. In addition, an Ena1 serine and threonine (ST)-rich patch, proposed to be targeted for phosphorylation by casein kinases, was also required for its uptake. Interestingly, our data suggest that this phosphorylation was not needed for cargo ubiquitylation. Furthermore, epsin-mediated internalization of Ena1 required a specific spatial organization of the ST patch with respect to K1090 within the cytoplasmic tail of the pump. We hypothesize that ubiquitylation and phosphorylation of Ena1 are required for epsin-mediated internalization.

scholarly journals Sequence and topology of a model intracellular membrane protein, E1 glycoprotein, from a coronavirus

Nature ◽  
1984 ◽  
Vol 308 (5961) ◽  
pp. 751-752 ◽  
Author(s):  
John Armstrong ◽  
Heiner Niemann ◽  
Sjef Smeekens ◽  
Peter Rottier ◽  
Graham Warren
Keyword(s):  
Membrane Protein ◽  
Intracellular Membrane ◽  
And Topology

A Partial Failure of Membrane Protein Turnover May Cause Alzheimers Disease: A New Hypothesis

2006 ◽  
Vol 3 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Kumar Sambamurti ◽  
Anitha Suram ◽  
Chitra Venugopal ◽  
Annamalai Prakasam ◽  
Yan Zhou ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Protein Turnover ◽  
Alzheimers Disease ◽  
Partial Failure ◽  
New Hypothesis

scholarly journals The yeast integral membrane protein Apq12 potentially links membrane dynamics to assembly of nuclear pore complexes

2007 ◽  
Vol 178 (5) ◽  
pp. 799-812 ◽  
Author(s):  
John J. Scarcelli ◽  
Christine A. Hodge ◽  
Charles N. Cole
Keyword(s):  
Membrane Protein ◽  
Integral Membrane Protein ◽  
Membrane Dynamics ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Cold Sensitive ◽  
Low Levels ◽  
Lower Temperature ◽  
Pore Complexes ◽  
And Function

Although the structure and function of components of the nuclear pore complex (NPC) have been the focus of many studies, relatively little is known about NPC biogenesis. In this study, we report that Apq12 is required for efficient NPC biogenesis in Saccharomyces cerevisiae. Apq12 is an integral membrane protein of the nuclear envelope (NE) and endoplasmic reticulum. Cells lacking Apq12 are cold sensitive for growth, and a subset of their nucleoporins (Nups), those that are primarily components of the cytoplasmic fibrils of the NPC, mislocalize to the cytoplasm. APQ12 deletion also causes defects in NE morphology. In the absence of Apq12, most NPCs appear to be associated with the inner but not the outer nuclear membrane. Low levels of benzyl alcohol, which increases membrane fluidity, prevented Nup mislocalization and restored the proper localization of Nups that had accumulated in cytoplasmic foci upon a shift to lower temperature. Thus, Apq12p connects nuclear pore biogenesis to the dynamics of the NE.

scholarly journals Initial ciliary assembly in Chlamydomonas requires Arp2/3-dependent recruitment from a ciliary protein reservoir in the plasma membrane

2020 ◽  
Author(s):  
Brae M Bigge ◽  
Nicholas E Rosenthal ◽  
David Sept ◽  
Courtney M Schroeder ◽  
Prachee Avasthi
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Long Range ◽  
Protein Targeting ◽  
Basal Bodies ◽  
Cell Periphery ◽  
Filamentous Actin ◽  
Actin Networks ◽  
Ciliary Protein ◽  
Broad Approach

ABSTRACTCilia are organelles important for signaling and motility. They are composed of microtubules ensheathed in plasma membrane. The mechanisms related to ciliogenesis also require another cytoskeletal element, actin, which has been shown to be important for organizing the basal bodies and transition zone at the base of cilia and for short- and long-range trafficking. However, most studies of actin’s role in ciliogenesis have taken a broad approach by knocking out all filamentous actin until now. Here, we more delicately dissect the interplay between actin and cilia by specifically focusing on actin networks nucleated by the Arp2/3 complex in Chlamydomonas. We find that knocking out Arp2/3-mediated actin networks dramatically impairs ciliary assembly and maintenance in these cells, and these defects are due to a problem with incorporation and gating of existing ciliary proteins, particularly in the early stages of assembly. We also show that cells lacking the Arp2/3 complex have more dramatic defects in ciliary maintenance using material from non-Golgi sources. Finally, we find relocalization of a ciliary membrane protein from the cell periphery to the cilia by internalization is dependent on actin and the Arp2/3 complex. Based on these results, we propose a new model of ciliary protein targeting during early ciliogenesis in which proteins previously targeted from the Golgi to the plasma membrane are reclaimed from this reservoir by Arp2/3-mediated networks.

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