Acute pyelonephritis: increased plasma membrane targeting of renal aquaporin‐2

ABSTRACT The retroviral Gag protein is capable of directing the production and release of virus-like particles in the absence of all other viral components. Budding normally occurs after Gag is transported to the plasma membrane by its membrane-targeting and -binding (M) domain. In the Rous sarcoma virus (RSV) Gag protein, the M domain is contained within the first 86 amino acids. When M is deleted, membrane association and budding fail to occur. Budding is restored when M is replaced with foreign membrane-binding sequences, such as that of the Src oncoprotein. Moreover, the RSV M domain is capable of targeting heterologous proteins to the plasma membrane. Although the solution structure of the RSV M domain has been determined, the mechanism by which M specifically targets Gag to the plasma membrane rather than to one or more of the large number of internal membrane surfaces (e.g., the Golgi apparatus, endoplasmic reticulum, and nuclear, mitochondrial, or lysosomal membranes) is unknown. To further investigate the requirements for targeting proteins to discrete cellular locations, we have replaced the M domain of RSV with the product of the unique long region 11 (UL11) gene of herpes simplex virus type 1. This 96-amino-acid myristylated protein is thought to be involved in virion transport and envelopment at internal membrane sites. When the first 100 amino acids of RSV Gag (including the M domain) were replaced by the entire UL11 sequence, the chimeric protein localized at and budded into the Golgi apparatus rather than being targeted to the plasma membrane. Myristate was found to be required for this specific targeting, as were the first 49 amino acids of UL11, which contain an acidic cluster motif. In addition to shedding new light on UL11, these experiments demonstrate that RSV Gag can be directed to internal cellular membranes and suggest that regions outside of the M domain do not contain a dominant plasma membrane-targeting motif.

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High level expression of transfected G protein αi3subunit is required for plasma membrane targeting and adenylyl cyclase inhibition in NIH 3T3 fibroblasts

FEBS Letters ◽

10.1016/0014-5793(92)80940-i ◽

1992 ◽

Vol 312 (2-3) ◽

pp. 223-228 ◽

Cited By ~ 15

Author(s):

Sylvie Hermouet ◽

Philippe de Mazancourt ◽

Allen M. Spiegel ◽

Marilyn Gist Farquhar ◽

Bridget S. Wilson

Keyword(s):

Plasma Membrane ◽

Adenylyl Cyclase ◽

G Protein ◽

Membrane Targeting ◽

High Level Expression ◽

3T3 Fibroblasts ◽

High Level ◽

Nih 3T3

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Role of the Gag Matrix Domain in Targeting Human Immunodeficiency Virus Type 1 Assembly

Journal of Virology ◽

10.1128/jvi.74.6.2855-2866.2000 ◽

2000 ◽

Vol 74 (6) ◽

pp. 2855-2866 ◽

Cited By ~ 185

Author(s):

Akira Ono ◽

Jan M. Orenstein ◽

Eric O. Freed

Keyword(s):

Human Immunodeficiency Virus ◽

Plasma Membrane ◽

Virus Particle ◽

Particle Formation ◽

Membrane Targeting ◽

Basic Domain ◽

Golgi Vesicles ◽

Immunodeficiency Virus ◽

Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) particle formation and the subsequent initiation of protease-mediated maturation occur predominantly on the plasma membrane. However, the mechanism by which HIV-1 assembly is targeted specifically to the plasma membrane versus intracellular membranes is largely unknown. Previously, we observed that mutations between residues 84 and 88 of the matrix (MA) domain of HIV-1 Gag cause a retargeting of virus particle formation to an intracellular site. In this study, we demonstrate that the mutant virus assembly occurs in the Golgi or in post-Golgi vesicles. These particles undergo core condensation in a protease-dependent manner, indicating that virus maturation can occur not only on the plasma membrane but also in the Golgi or post-Golgi vesicles. The intracellular assembly of mutant particles is dependent on Gag myristylation but is not influenced by p6Gag or envelope glycoprotein expression. Previous characterization of viral revertants suggested a functional relationship between the highly basic domain of MA (amino acids 17 to 31) and residues 84 to 88. We now demonstrate that mutations in the highly basic domain also retarget virus particle formation to the Golgi or post-Golgi vesicles. Although the basic domain has been implicated in Gag membrane binding, no correlation was observed between the impact of mutations on membrane binding and Gag targeting, indicating that these two functions of MA are genetically separable. Plasma membrane targeting of Gag proteins with mutations in either the basic domain or between residues 84 and 88 was rescued by coexpression with wild-type Gag; however, the two groups of MA mutants could not rescue each other. We propose that the highly basic domain of MA contains a major determinant of HIV-1 Gag plasma membrane targeting and that mutations between residues 84 and 88 disrupt plasma membrane targeting through an effect on the basic domain.

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Mechanisms of plasma membrane targeting of formin mDia2 through its amino terminal domains

Molecular Biology of the Cell ◽

10.1091/mbc.e10-03-0256 ◽

2011 ◽

Vol 22 (2) ◽

pp. 189-201 ◽

Cited By ~ 40

Author(s):

Roman Gorelik ◽

Changsong Yang ◽

Vasumathi Kameswaran ◽

Roberto Dominguez ◽

Tatyana Svitkina

Keyword(s):

Plasma Membrane ◽

Electrostatic Interactions ◽

Coiled Coil ◽

Small Gtpases ◽

Coincidence Detection ◽

Membrane Targeting ◽

Amino Terminal ◽

N Terminus

The formin mDia2 mediates the formation of lamellipodia and filopodia during cell locomotion. The subcellular localization of activated mDia2 depends on interactions with actin filaments and the plasma membrane. We investigated the poorly understood mechanism of plasma membrane targeting of mDia2 and found that the entire N-terminal region of mDia2 preceding the actin-polymerizing formin homology domains 1 and 2 (FH1–FH2) module was potently targeted to the membrane. This localization was enhanced by Rif, but not by other tested small GTPases, and depended on a positively charged N-terminal basic domain (BD). The BD bound acidic phospholipids in vitro, suggesting that in vivo it may associate with the plasma membrane through electrostatic interactions. Unexpectedly, a fragment consisting of the GTPase-binding region and the diaphanous inhibitory domain (G-DID), thought to mediate the interaction with GTPases, was not targeted to the plasma membrane even in the presence of constitutively active Rif. Addition of the BD or dimerization/coiled coil domains to G-DID rescued plasma membrane targeting in cells. Direct binding of Rif to mDia2 N terminus required the presence of both G and DID. These results suggest that the entire N terminus of mDia2 serves as a coincidence detection module, directing mDia2 to the plasma membrane through interactions with phospholipids and activated Rif.

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Chlorpromazine Induces Basolateral Aquaporin-2 Accumulation via F-Actin Depolymerization and Blockade of Endocytosis in Renal Epithelial Cells

Cells ◽

10.3390/cells9041057 ◽

2020 ◽

Vol 9 (4) ◽

pp. 1057

Author(s):

Richard Bouley ◽

Naofumi Yui ◽

Abby Terlouw ◽

Pui W. Cheung ◽

Dennis Brown

Keyword(s):

Plasma Membrane ◽

Epithelial Cells ◽

Mdck Cells ◽

Rat Kidney ◽

Apical Plasma Membrane ◽

Rhodamine Phalloidin ◽

Renal Epithelial Cells ◽

Aquaporin 2 ◽

Basolateral Plasma Membrane

We previously showed that in polarized Madin–Darby canine kidney (MDCK) cells, aquaporin-2 (AQP2) is continuously targeted to the basolateral plasma membrane from which it is rapidly retrieved by clathrin-mediated endocytosis. It then undertakes microtubule-dependent transcytosis toward the apical plasma membrane. In this study, we found that treatment with chlorpromazine (CPZ, an inhibitor of clathrin-mediated endocytosis) results in AQP2 accumulation in the basolateral, but not the apical plasma membrane of epithelial cells. In MDCK cells, both AQP2 and clathrin were concentrated in the basolateral plasma membrane after CPZ treatment (100 µM for 15 min), and endocytosis was reduced. Then, using rhodamine phalloidin staining, we found that basolateral, but not apical, F-actin was selectively reduced by CPZ treatment. After incubation of rat kidney slices in situ with CPZ (200 µM for 15 min), basolateral AQP2 and clathrin were increased in principal cells, which simultaneously showed a significant decrease of basolateral compared to apical F-actin staining. These results indicate that clathrin-dependent transcytosis of AQP2 is an essential part of its trafficking pathway in renal epithelial cells and that this process can be inhibited by selectively depolymerizing the basolateral actin pool using CPZ.

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