Talk:Lipid raft

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Untitled section

In the latest issue of Nature (2008 Dec 21, advance online publication) there's a letter on lipid diffusion in the plasma membrane of living cells on length scales down to a few tens of nanometers. I cannot judge whether it is of relevance to this article. Someone more knowledgeable might want to have a look ("Direct observation of the nanoscale dynamics of membrane lipids in a living cell". Nature doi:10.1038/nature07596).

I'm not really convinced about the existence of lipid rafts. I'm not really sure what they are.

Their existence is still debated. A good recent review on the subject is from Sean Munro: Lipid rafts: elusive or illusive? Cell. 2003 Nov 14;115(4):377-88. Cjb88 20:14, 24 Jan 2005 (UTC)

The lipid raft is a hypothesis with evidence supporting and refuting it. This article should be structured in such a way that someone who is not an expert can understand that lipid rafts may be a model that is completely abandoned at some point, or that it may become the dominant model. — Preceding unsigned comment added by 68.45.59.164 (talk) 03:46, 17 April 2012 (UTC)

I am a 4th-year biomedical engineering student at the University of Virginia currently working on imaging the surface of lipid rafts and obtaining some of their mechanical properties. I added some background information on lipid rafts that I've come across over the past few months. Sonrisa102 21:09, 13 December 2005 (UTC)

"Also because of this difference in saturation levels, the raft areas exhibit a higher melting point than the surrounding phospholipids." This statement is speculation, how is it possible to prove this? DSC will not show this.Rvlaw

"In addition, the increased concentration of cholesterol in the rafts further increases their rigidity." Again - what does "rigidity" mean in terms of a fluid? Does the author mean viscosity?Rvlaw

"part of the membrane (Henderson et al, 2004). Lipid rafts also differ from the rest of the membrane in that they are resistant to non-ionic detergents, such as Triton X-100. When the detergent is added to cells, the fluid membrane will associate into solution while the lipid rafts will remain in tact and can be extracted. Because of their composition and detergent resistance, lipid rafts may also be referred to as detergent-insoluble, glycolipid-enriched complexes, or DIGs (Dietrich & Jacobson, 1999). However, the validity of the detergent resistance methodology of membranes has recently been called into question. (Heerklotz, 2002)"

Not sure why this was removed. Whilst I agree that this technique is now seen as problematic, it was the basis of the technique from the beginningRvlaw 20:56, 14 January 2006 (UTC)

"A two-dimensional lipid bilayer may exist in a liquid or solid phase depending on whether the temperature is above or below the lipid melting temperature. In the solid phase, the lipids are immobile, packed tightly and with their hydrocarbon taild hightly ordered. As the temperature is increases a phase transition occurs and the packing becomes more loose and the lipids become more mobile. In the presence of cholesterol however a third phase is possible - the liquid-ordered phase. Cholesterol imposes order on near by tails allowing the lipids to remain mobiole but be tightly packed. This process is facilitated if the lipids contain highly saturated tails such as those found in sphingolipids." -This information is already found in the links.Rvlaw

"caused by the missmatch in the length of the hydrophobic tails arrising due to the packing and differences in saturation."Rvlaw - This is not the only cause of fluid-fluid immiscibility

History

I am disappointed that the really seminal article in this field from Bretscher and Munro (Science 1993 volume 261 page 1280) is not cited.(Dingwallcm (talk) 18:00, 28 October 2009 (UTC))

Image

Sorry about the layout... I'm not able at all. May someone correct it?

thanks a lot!!

Role of rafts

I think this page could really do with a section summarising the role of rafts in cells. e.g. discussion of T cell receptor localisation and signalling, hijacking of cell signalling by bacteria such as Salmonella using rafts domains in the host cell etc. 82.211.95.178 10:34, 30 August 2007 (UTC)

sphingolipid tails

Hi. In the topmost figure (with the blue background), why are the sphingolipids shown as having three hydrocarbon chains in the tail instead of two? Kenmcl2 (talk) 21:31, 4 December 2007 (UTC)

because they are super sphingolipids. your right, it should be 2 —Preceding unsigned comment added by 66.130.90.42 (talk) 18:32, 10 April 2008 (UTC)

NPOV violated?

I think the following sentence should be deleted, because it breaks the neutral point of view policy:

The Kusumi lab are some of the leaders in this field of raft study.--Don severo (talk) 17:37, 31 October 2009 (UTC)

You are right, thanks for the information. I removed the sentence. Panoramix303 (talk) 20:27, 31 October 2009 (UTC)

TMI

This article is heavy with extraneous detail. An example is the recounting of the IgE signaling pathway with barely any mention of how a raft is significant to it. The T cell signaling section has more detail than the wiki page on the T cell receptor. Some of this article was obviously taken straight from research papers, including past tense explanations of specific events in single studies. Overkill puts off readers. It's our job to sift so everybody else doesn't have to.

173.25.54.191 (talk) 01:48, 31 October 2013 (UTC)

Citations needed in introduction section

"Although more common in plasma membrane, lipid rafts have also been reported in other parts of the cell, such as the Golgi apparatus and lysosomes." In this particular sentence, I feel that a citation is needed to indicate from what source(s) "lipid rafts have been reported in other parts of the cell. . . " The previous references listed in the introduction have no mention of lipid rafts being found in lysosomes. Reference 5 does mention lipid raft assembly in the Golgi complex; however, this sentence still requires an adequate citation. --Wallace169 (talk) 23:29, 30 September 2016 (UTC)

Role in signal transduction

"Lipid rafts have been found by researchers to be involved in many signal transduction processes, such as Immunoglobulin E signaling . . . and so on. " The use of "and so on" may come across as informal and unprofessional to readers. This phrase appears vague and and might leave the reader wondering what other signal transduction processes lipid rafts are involved in. My suggestion would be to omit the phrase altogether and end the sentence as ". . . B cell antigen receptor signalling, EGF receptor signaling, and insulin receptor signaling." --Wallace169 (talk) 00:29, 1 October 2016 (UTC)

Good pick up. The sentence is in the passive voice, as well. It is possible that "and so on" was a replacement for "etc." in a close paraphrase. the following sentence ("In order to illustrate these principles, detailed examples of signalling pathways that involve lipid rafts are described below.") is very similar to a sentence in reference 24: Lipid rafts and signal transduction (Nature Reviews Molecular Cell Biology 1:31-39 October 2000) (current ref 24). A closer look is in order, and the laziness may go beyond casual phrasing. I don't have time to dig deeper at this instant, but please don't let me drop the ball on this issue. The change you suggested is appropriate. BiologicalMe (talk) 02:47, 1 October 2016 (UTC)

After a closer examination, there are more parallels. For example, references 25-27 in the IgE signalling section of the current version of the article correspond to references 39–41 in the source article. Additionally, there is content that is far too technical for Wikipedia that is found in the source (Triton X-100 solubility). A lot of cleanup is warranted. I'd say that I'd be right on it if the next few weeks didn't look hectic. BiologicalMe (talk) 16:12, 1 October 2016 (UTC)

Copyright problem removed

Prior content in this article duplicated one or more previously published sources. The material was copied from: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.458.3176&rep=rep1&type=pdf http://themedicalbiochemistrypage.org/signal-transduction.php#intro. Copied or closely paraphrased material has been rewritten or removed and must not be restored, unless it is duly released under a compatible license. (For more information, please see "using copyrighted works from others" if you are not the copyright holder of this material, or "donating copyrighted materials" if you are.)

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Original URL is live. BiologicalMe (talk) 18:08, 16 May 2017 (UTC)