scholarly journals Akt signaling dynamics in plasma membrane microdomains visualized by FRET-based reporters

2009 ◽  
Vol 2 (1) ◽  
pp. 32-34 ◽  
Author(s):  
Xinxin Gao ◽  
Jin Zhang
Keyword(s):  
Plasma Membrane ◽  
Akt Signaling ◽  
Membrane Microdomains ◽  
Signaling Dynamics ◽  
Plasma Membrane Microdomains

scholarly journals PI3K/Akt signaling requires spatial compartmentalization in plasma membrane microdomains

2011 ◽  
Vol 108 (35) ◽  
pp. 14509-14514 ◽  
Author(s):  
X. Gao ◽  
P. R. Lowry ◽  
X. Zhou ◽  
C. Depry ◽  
Z. Wei ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Akt Signaling ◽  
Membrane Microdomains ◽  
Plasma Membrane Microdomains

scholarly journals Flotillin microdomains interact with the cortical cytoskeleton to control uropod formation and neutrophil recruitment

2010 ◽  
Vol 191 (4) ◽  
pp. 771-781 ◽  
Author(s):  
Alexander Ludwig ◽  
Grant P. Otto ◽  
Kirsi Riento ◽  
Emily Hams ◽  
Padraic G. Fallon ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Ex Vivo ◽  
Neutrophil Migration ◽  
Neutrophil Recruitment ◽  
Membrane Microdomains ◽  
Neutrophil Chemotaxis ◽  
Myosin Iia ◽  
Plasma Membrane Microdomains ◽  
Cortical Cytoskeleton

We studied the function of plasma membrane microdomains defined by the proteins flotillin 1 and flotillin 2 in uropod formation and neutrophil chemotaxis. Flotillins become concentrated in the uropod of neutrophils after exposure to chemoattractants such as N-formyl-Met-Leu-Phe (fMLP). Here, we show that mice lacking flotillin 1 do not have flotillin microdomains, and that recruitment of neutrophils toward fMLP in vivo is reduced in these mice. Ex vivo, migration of neutrophils through a resistive matrix is reduced in the absence of flotillin microdomains, but the machinery required for sensing chemoattractant functions normally. Flotillin microdomains specifically associate with myosin IIa, and spectrins. Both uropod formation and myosin IIa activity are compromised in flotillin 1 knockout neutrophils. We conclude that the association between flotillin microdomains and cortical cytoskeleton has important functions during neutrophil migration, in uropod formation, and in the regulation of myosin IIa.

scholarly journals Topography of plasma membrane microdomains and its consequences for mast cell signaling

2006 ◽  
Vol 36 (10) ◽  
pp. 2795-2806 ◽  
Author(s):  
Petr Heneberg ◽  
Pavel Lebduška ◽  
L'ubica Dráberová ◽  
Jan Korb ◽  
Petr Dráber
Keyword(s):  
Mast Cell ◽  
Plasma Membrane ◽  
Cell Signaling ◽  
Membrane Microdomains ◽  
Plasma Membrane Microdomains

scholarly journals Yeast cell wall integrity sensors form specific plasma membrane microdomains important for signalling

2016 ◽  
Vol 18 (9) ◽  
pp. 1251-1267 ◽  
Author(s):  
Christian Kock ◽  
Henning Arlt ◽  
Christian Ungermann ◽  
Jürgen J. Heinisch
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Yeast Cell ◽  
Cell Wall Integrity ◽  
Yeast Cell Wall ◽  
Membrane Microdomains ◽  
Plasma Membrane Microdomains

scholarly journals DC-SIGN and Influenza Hemagglutinin Dynamics in Plasma Membrane Microdomains Are Markedly Different

2011 ◽  
Vol 100 (11) ◽  
pp. 2662-2670 ◽  
Author(s):  
Michelle S. Itano ◽  
Aaron K. Neumann ◽  
Ping Liu ◽  
Feng Zhang ◽  
Enrico Gratton ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Microdomains ◽  
Influenza Hemagglutinin ◽  
Plasma Membrane Microdomains

scholarly journals Palmitoylated Cysteines in Chikungunya Virus nsP1 Are Critical for Targeting to Cholesterol-Rich Plasma Membrane Microdomains with Functional Consequences for Viral Genome Replication

2020 ◽  
Vol 94 (10) ◽  
Author(s):  
William Bakhache ◽  
Aymeric Neyret ◽  
Eric Bernard ◽  
Andres Merits ◽  
Laurence Briant
Keyword(s):  
Plasma Membrane ◽  
Lipid Bilayers ◽  
Functional Role ◽  
Membrane Microdomains ◽  
Genome Replication ◽  
Functional Importance ◽  
Late Endosomes ◽  
Plasma Membrane Microdomains ◽  
Insight Into

ABSTRACT In mammalian cells, alphavirus replication complexes are anchored to the plasma membrane. This interaction with lipid bilayers is mediated through the viral methyl/guanylyltransferase nsP1 and reinforced by palmitoylation of cysteine residue(s) in the C-terminal region of this protein. Lipid content of membranes supporting nsP1 anchoring remains poorly studied. Here, we explore the membrane binding capacity of nsP1 with regard to cholesterol. Using the medically important chikungunya virus (CHIKV) as a model, we report that nsP1 cosegregates with cholesterol-rich detergent-resistant membrane microdomains (DRMs), also called lipid rafts. In search for the critical factor for cholesterol partitioning, we identify nsP1 palmitoylated cysteines as major players in this process. In cells infected with CHIKV or transfected with CHIKV trans-replicase plasmids, nsP1, together with the other nonstructural proteins, are detected in DRMs. While the functional importance of CHIKV nsP1 preference for cholesterol-rich membrane domains remains to be determined, we observed that U18666A- and imipramine-induced sequestration of cholesterol in late endosomes redirected nsP1 to these compartments and simultaneously dramatically decreased CHIKV genome replication. A parallel study of Sindbis virus (SINV) revealed that nsP1 from this divergent alphavirus displays a low affinity for cholesterol and only moderately segregates with DRMs. Behaviors of CHIKV and SINV with regard to cholesterol, therefore, match with the previously reported differences in the requirement for nsP1 palmitoylation, which is dispensable for SINV but strictly required for CHIKV replication. Altogether, this study highlights the functional importance of nsP1 segregation with DRMs and provides new insight into the functional role of nsP1 palmitoylated cysteines during alphavirus replication. IMPORTANCE Functional alphavirus replication complexes are anchored to the host cell membranes through the interaction of nsP1 with the lipid bilayers. In this work, we investigate the importance of cholesterol for such an association. We show that nsP1 has affinity for cholesterol-rich membrane microdomains formed at the plasma membrane and identify conserved palmitoylated cysteine(s) in nsP1 as the key determinant for cholesterol affinity. We demonstrate that drug-induced cholesterol sequestration in late endosomes not only redirects nsP1 to this compartment but also dramatically decreases genome replication, suggesting the functional importance of nsP1 targeting to cholesterol-rich plasma membrane microdomains. Finally, we show evidence that nsP1 from chikungunya and Sindbis viruses displays different sensitivity to cholesterol sequestering agents that parallel with their difference in the requirement for nsP1 palmitoylation for replication. This research, therefore, gives new insight into the functional role of palmitoylated cysteines in nsP1 for the assembly of functional alphavirus replication complexes in their mammalian host.

What Can Epitope Specific Antibodies Tell us About the Organization of Caveolin in Cells?

2001 ◽  
Vol 7 (S2) ◽  
pp. 1030-1031
Author(s):  
J.M. Robinson
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Biochemical Characterization ◽  
Cell Types ◽  
Membrane Microdomains ◽  
Truncated Form ◽  
Coated Pits ◽  
N Terminus ◽  
Plasma Membrane Microdomains

There are three members of the caveolin (CAV) gene family that give rise to four polypeptides. These polypeptides are CAV-1α, CAV-1β, CAV-2, and CAV-3. The CAV-1β isoform is a truncated form of CAV-1α that lacks 31 amino acids at the N-terminus of the molecule. The CAV- 1β molecule arises through an alternative splicing mechanism.Caveolae are specialized plasma membrane microdomains that are expressed at high levels in some cell types (e.g., endothelium, adipocytes, fibroblasts). These specialized regions of the plasma membrane have a characteristic omega-shaped appearance with diameters ranging from 40-90 run. They are distinct from clathrin-coated pits since they lack the characteristic coated appearance in electron microscopy. Caveolae were among the first structures to be discovered by biological electron microscopy. However, biochemical characterization of these structures did not begin in earnest until a marker protein was identified. The initial marker was the 22-kDa protein known as caveolin.

scholarly journals Lateral segregation of neutrophil chemotactic receptors into actin- and fodrin-rich plasma membrane microdomains depleted in guanyl nucleotide regulatory proteins.

1988 ◽  
Vol 107 (3) ◽  
pp. 921-928 ◽  
Author(s):  
A J Jesaitis ◽  
G M Bokoch ◽  
J O Tolley ◽  
R A Allen
Keyword(s):  
Plasma Membrane ◽  
Cytoskeletal Proteins ◽  
Regulatory Proteins ◽  
Membrane Microdomains ◽  
Human Neutrophils ◽  
Western Blots ◽  
Sds Page ◽  
Formyl Peptide ◽  
Plasma Membrane Microdomains ◽  
Lateral Segregation

Subcellular fractions were prepared from human neutrophils desensitized at 15 degrees C with stimulatory doses of the photoaffinity derivative F-Met-Leu-Phe-N epsilon-(2-(rho-azido[125I]salicylamido)ethyl-1,3'- dithio-propionyl)-Lys. The covalently labeled receptors were found in a membrane fraction of higher density than those from cells preexposed to ligand at 4 degrees C but not desensitized. The denser fraction (rho approximately equal to 1.155 g/cc) was the cellular locus of the membrane associated cytoskeletal proteins, actin, and fodrin, as detected immunologically on western blots. The light fraction (rho approximately equal to 1.135), cosedimented with neutrophil plasma membrane markers, plasma membrane guanyl nucleotide regulatory proteins, and several characteristic polypeptides identified by SDS-PAGE, including a major 72-kD species. The photoaffinity-labeled species in either case showed the same mobility on SDS-PAGE (Mr = 50,000-70,000) corresponding to previously reported values for N-formyl chemotactic receptors. These labeled receptors were sensitive to proteolysis after exposure of the intact photoaffinity-labeled cells to papain at 4 degrees C. We conclude that (a) the fractions isolated are probably derived from different lateral microdomains of the surface of human neutrophils; (b) the higher density fraction contains occupied N-formyl-chemotactic receptors previously shown to have been converted, to a high affinity, slowly dissociating form coisolating with neutrophil cytoskeleton and implicated in the termination of formyl peptide-induced neutrophil activation; and (c) the translocation of receptors to these microdomains may serve to compartmentalize receptors and perhaps regulate the interaction of the receptor/G-protein transduction pair.

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