Lipid Rafts, Detergent-Resistant Membranes, and Raft Targeting Signals

Physiology ◽  
2006 ◽  
Vol 21 (6) ◽  
pp. 430-439 ◽  
Author(s):  
Deborah A. Brown
Keyword(s):  
Lipid Rafts ◽  
Protein Function ◽  
Biological Membranes ◽  
Major Revision ◽  
Liquid Ordered ◽  
Cell Processes ◽  
Detergent Resistant Membranes ◽  
Targeting Signals

Lipid rafts are liquid-ordered (lo) phase microdomains proposed to exist in biological membranes. Rafts have been widely studied by isolating lo-phase detergent-resistant membranes (DRMs) from cells. Recent findings have shown that DRMs are not the same as preexisting rafts, prompting a major revision of the raft model. Nevertheless, raft-targeting signals identified by DRM analysis are often required for protein function, implicating rafts in a variety of cell processes.

scholarly journals What Can Mushroom Proteins Teach Us about Lipid Rafts?

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 264
Author(s):  
Maja Grundner ◽  
Anastasija Panevska ◽  
Kristina Sepčić ◽  
Matej Skočaj
Keyword(s):  
Lipid Rafts ◽  
Lipid Raft ◽  
Mammalian Cells ◽  
Binding Proteins ◽  
Protein Complexes ◽  
Biological Membranes ◽  
Indirect Evidence ◽  
Lipid Binding ◽  
Liquid Ordered

The lipid raft hypothesis emerged as a need to explain the lateral organization and behavior of lipids in the environment of biological membranes. The idea, that lipids segregate in biological membranes to form liquid-disordered and liquid-ordered states, was faced with a challenge: to show that lipid-ordered domains, enriched in sphingomyelin and cholesterol, actually exist in vivo. A great deal of indirect evidence and the use of lipid-binding probes supported this idea, but there was a lack of tools to demonstrate the existence of such domains in living cells. A whole new toolbox had to be invented to biochemically characterize lipid rafts and to define how they are involved in several cellular functions. A potential solution came from basic biochemical experiments in the late 1970s, showing that some mushroom extracts exert hemolytic activities. These activities were later assigned to aegerolysin-based sphingomyelin/cholesterol-specific cytolytic protein complexes. Recently, six sphingomyelin/cholesterol binding proteins from different mushrooms have been identified and have provided some insight into the nature of sphingomyelin/cholesterol-rich domains in living vertebrate cells. In this review, we dissect the accumulated knowledge and introduce the mushroom lipid raft binding proteins as molecules of choice to study the dynamics and origins of these liquid-ordered domains in mammalian cells.

scholarly journals Gag Regulates Association of Human Immunodeficiency Virus Type 1 Envelope with Detergent-Resistant Membranes

2006 ◽  
Vol 80 (11) ◽  
pp. 5292-5300 ◽  
Author(s):  
Jayanta Bhattacharya ◽  
Alexander Repik ◽  
Paul R. Clapham
Keyword(s):  
Human Immunodeficiency Virus ◽  
Lipid Rafts ◽  
Human Immunodeficiency Virus Type ◽  
Cytoplasmic Domain ◽  
Virus Particles ◽  
Immunodeficiency Virus ◽  
Detergent Resistant Membranes ◽  
Envelope Incorporation ◽  
Hiv 1

ABSTRACT Assembly of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein on budding virus particles is important for efficient infection of target cells. In infected cells, lipid rafts have been proposed to form platforms for virus assembly and budding. Gag precursors partly associate with detergent-resistant membranes (DRMs) that are believed to represent lipid rafts. The cytoplasmic domain of the envelope gp41 usually carries palmitate groups that were also reported to confer DRM association. Gag precursors confer budding and carry envelope glycoproteins onto virions via specific Gag-envelope interactions. Thus, specific mutations in both the matrix domain of the Gag precursor and gp41 cytoplasmic domain abrogate envelope incorporation onto virions. Here, we show that HIV-1 envelope association with DRMs is directly influenced by its interaction with Gag. Thus, in the absence of Gag, envelope fails to associate with DRMs. A mutation in the p17 matrix (L30E) domain in Gag (Gag L30E) that abrogates envelope incorporation onto virions also eliminated envelope association with DRMs in 293T cells and in the T-cell line, MOLT 4. These observations are consistent with a requirement for an Env-Gag interaction for raft association and subsequent assembly onto virions. In addition to this observation, we found that mutations in the gp41 cytoplasmic domain that abrogated envelope incorporation onto virions and impaired infectivity of cell-free virus also eliminated envelope association with DRMs. On the basis of these observations, we propose that Gag-envelope interaction is essential for efficient envelope association with DRMs, which in turn is essential for envelope budding and assembly onto virus particles.

scholarly journals Electron Spin Resonance Characterization of Liquid Ordered Phase of Detergent-Resistant Membranes from RBL-2H3 Cells

1999 ◽  
Vol 77 (2) ◽  
pp. 925-933 ◽  
Author(s):  
Mingtao Ge ◽  
Kenneth A. Field ◽  
Rajindra Aneja ◽  
David Holowka ◽  
Barbara Baird ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Spin Resonance ◽  
Liquid Ordered ◽  
Detergent Resistant Membranes

Lipid Rafts: Feeling is Believing

Physiology ◽  
2004 ◽  
Vol 19 (2) ◽  
pp. 39-43 ◽  
Author(s):  
Robert M. Henderson ◽  
J. Michael Edwardson ◽  
Nicholas A. Geisse ◽  
David E. Saslowsky
Keyword(s):  
Atomic Force Microscopy ◽  
Recent Work ◽  
Lipid Rafts ◽  
Biological Membranes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Factors Influencing ◽  
And Behavior

In the late 1990s, accumulated evidence led to the proposal that biological membranes are composed of microdomains of different lipids, which form functional “rafts.” Recent work using atomic force microscopy has given us new insights into the factors influencing the formation and behavior of these physiological microenvironments

scholarly journals Analysis of Detergent-Resistant Membranes in Arabidopsis. Evidence for Plasma Membrane Lipid Rafts

2004 ◽  
Vol 137 (1) ◽  
pp. 104-116 ◽  
Author(s):  
Georg H.H. Borner ◽  
D. Janine Sherrier ◽  
Thilo Weimar ◽  
Louise V. Michaelson ◽  
Nathan D. Hawkins ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Lipid Rafts ◽  
Membrane Lipid ◽  
Plasma Membrane Lipid ◽  
Detergent Resistant Membranes

CLN3P, the Batten disease protein, localizes to membrane lipid rafts (detergent-resistant membranes)

2004 ◽  
Vol 317 (4) ◽  
pp. 988-991 ◽  
Author(s):  
Dinesh Rakheja ◽  
Srinivas B Narayan ◽  
Johanne V Pastor ◽  
Michael J Bennett
Keyword(s):  
Lipid Rafts ◽  
Batten Disease ◽  
Membrane Lipid ◽  
Disease Protein ◽  
Detergent Resistant Membranes

scholarly journals LMP2A Does Not Require Palmitoylation To Localize to Buoyant Complexes or for Function

2004 ◽  
Vol 78 (20) ◽  
pp. 10878-10887 ◽  
Author(s):  
Rebecca B. Katzman ◽  
Richard Longnecker
Keyword(s):  
Lipid Rafts ◽  
Protein Function ◽  
Cell Receptor ◽  
Specific Protein ◽  
Membrane Microdomains ◽  
Acid Modification ◽  
Latent Membrane Protein 2A ◽  
Barr Virus ◽  
Latently Infected ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) latent membrane protein 2A (LMP2A) is expressed constitutively in lipid rafts in latently infected B lymphocytes. Lipid rafts are membrane microdomains enriched in cholesterol and sphingolipids selective for specific protein association. Lipid rafts have been shown to be necessary for B-cell receptor (BCR) signal transduction. LMP2A prevents BCR recruitment to lipid rafts, thereby abrogating BCR function. As LMP2A is palmitoylated, whether this fatty acid modification is necessary for LMP2A to localize to lipid rafts and for protein function was investigated. LMP2A palmitoylation was confirmed in latently infected B cells. LMP2A was found to be palmitoylated on multiple cysteines only by S acylation. An LMP2A mutant that was not palmitoylated was identified and functioned similar to wild-type LMP2A; unmodified LMP2A localized to lipid rafts, was tyrosine phosphorylated, was associated with LMP2A-associated proteins, was ubiquitinated, and was able to block calcium mobilization following BCR cross-linking. Therefore, palmitoylation of LMP2A is not required for LMP2A targeting to buoyant complexes or for function.

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