Lipid rafts: signaling and sorting platforms of cells and their roles in cancer

A retinoic acid receptor RARα pool present in membrane lipid rafts forms complexes with G protein αQ to activate p38MAPK

“…Whether there is a correlation between these observations and the resistance of such cancer cells to the antiproliferative action of RA would require further investigations, but is out of the scope of this study. Nevertheless, our results and others (Lai et al, 2008;White et al, 2008;Staubach and Hanisch, 2011) suggest that Gaq proteins, as well as several components of lipid rafts, would have an important role in the control of not only gene expression but also cell growth.…”

“…Remarkably, other signaling pathways involving Gaq proteins, such as the EGF pathway, are also affected in such cells. It is important to note that most signaling pathways are controlled by essential scaffolding proteins of lipid rafts such as caveolin-1 (Sugawara et al, 2007;Staubach and Hanisch, 2011). Moreover, caveolin-1 is frequently downregulated in erbB-2 positive cells (Park et al, 2005).…”

Function of Flotillins in Receptor Tyrosine Kinase Signaling and Endocytosis: Role of Tyrosine Phosphorylation and Oligomerization

“…However, recent research from several groups has revealed that endocytosis can be divided into numerous pathways, many of which do not require clathrin, and are thus designated as clathrin-independent. For a general introduction on endocytosis, the reader is referred to these excellent reviews (68)(69)(70). Some factors that regulate the clathrin independent pathways have been identified in the recent years, and it is clear that small GTPases such as Cdc42, Rho A or Arf (ADP ribosylation factor) family are involved, each determining their own endocytic pathway.…”

Overexpression of sigma-1 receptor inhibits ADAM10 and ADAM17 mediated shedding in vitro

“…Such profits have linked sigma-1 receptor to many diseases, such as drug addition, Alzheimer's disease, stroke, and depression (Maurice and Su, 2009). Sigma-1 receptor is also found to be highly expressed in many cancer cells (Vilner et al, 1995) and involved in regulating cancer cell proliferation by modifying lipid rafts (Palmer et al, 2007) Lipid rafts are membrane microdomains that are essential in signaling processes (Palmer et al, 2007;Staubach and Hanisch, 2011). Sigma-1 receptor is enriched with lipid raft markers caveolin-2 Su, 2003, 2007;Hayashi and Fujimoto, 2010) and they can modify lipid fluidity by remodeling lipid rafts Su, 2005, 2010;Palmer et al, 2007).…”