Commentary - Journal of Cell Biology and Metabolism (2023) Volume 5, Issue 2

Moving past lipid: the structure and usage of the plasma membrane

Department of Chemical Sciences, University of Illinois, Urbana, USA

*Corresponding Author:

Kevin Jerry
Department of Chemical Sciences
University of Illinois, Urbana, USA
E-mail: kevin@edu.com

Received: 29-Mar-2023, Manuscript No. AACBM-23-58687; Editor assigned: 31-Mar-2023, PreQC No. AACBM-23-58687 (PQ); Reviewed: 14-Apr-2023, QC No AACBM -23- 58687; Revised: 19-Apr-2023, Manuscript No. AACBM -23-58687 (R); Published: 26-Apr-2023, DOI:10.35841/aacbm-5.2.138

Citation: Jerry K. Moving past lipid: the structure and usage of the plasma membrane. J Cell Biol Metab. 2022;5(2):138

Introduction

In the plasma membranes of eukaryotic cells, there are thought to be small, dynamic, organized regions of cholesterol and sphingolipids known as "lipid rafts." The lipid raft hypothesis proposes that these sphingolipid- and cholesterol-enriched domains regulate the protein-protein interactions necessary for cellular function. The organization of plasma membranes, cell signaling, and other crucial biological processes are all influenced by the amount of cholesterol and sphingolipids present within the cell, as numerous studies have demonstrated. There is still a lack of data that clearly shows that lipid rafts exist in mammalian cells despite 15 years of investigation and the use of cutting-edge imaging techniques. This Perspective reviews the evidence refuting the lipid raft hypothesis and explores potential replacements for the existing theories regarding the structure of the plasma membrane and the role of lipids in cellular function [1].

A protein-centric perspective that assumed that proteins carried out the majority of membrane activities and that lipids just functioned as a solvent for protein transport formerly predominated plasma membrane research. The lipid raft hypothesis popularized the notion that lipids regulate membrane organization and function, despite the fact that the idea that lipids self-assemble into compositionally and functionally different regions inside the plasma membrane was not new. The theory proposed that advantageous molecular interactions trigger the creation of lipid rafts, or regions rich in cholesterol and sphingolipids, within the plasma membrane. The placement of each membrane protein inside the plasma membrane and, consequently, its closeness to potential binding partners, are controlled by the differences in their affinities for raft and nonraft lipid species. Initially, it was thought that lipid rafts served as sorting structures that mediated membrane traffic and cell signaling. Since then, additional cellular functions involving rafts have been proposed, and the definition of a lipid raft has changed. Lipid rafts are described as small, dynamic, ordered collections of proteins, sphingolipids, and cholesterol that can interact with one another, with other proteins, and with other molecules to form larger structures. The raft hypothesis continues to be founded on the idea that sphingolipids and cholesterol have the ability to self-organize [2].

The potential significance of lipid rafts has drawn a lot of fresh minds to the study of biological membranes. The lipid raft concept appears to have gained widespread acceptance after more than 15 years of research and is discussed in a number of recent textbooks. Nevertheless, the indirect nature of the data used to support the lipid raft theory prevents other possible explanations for these findings from being fully explored. Although cellular levels of cholesterol and sphingolipids obviously affect protein function, it is still unclear whether the lipid raft theory adequately describes the mechanism underlying this lipid-modulated protein activity. Contrary to a key assumption of the lipid raft hypothesis, the absence of cholesterol enrichment in the sphingolipid domains suggests that the self-organizing capacity of cholesterol and sphingolipids was not responsible for the organisation of the plasma membrane in the fibroblast cells. Another argument against the formation of lipid rafts is the lack of cholesterolenriched regions in the plasma membranes of these fibroblast cells. Nevertheless, it is impossible to rule out the possibility that the domains were smaller than the lateral resolution of the Nano SIMS analysis, that their enrichment was too low to be identified, or that the lipid distribution in fibroblast cells is quite different from that of other cell types [3].

The various pathways for cholesterol- and sphingolipidmediated protein structure and activity that have been proposed here need to be thoroughly tested because they are by no means all-inclusive. The processes that create the lipidmediated cellular activities that have been seen may be far more complex than those detailed here or those that have been postulated so far, given the intricacy of the various events that lead to cell signalling. Accurate modelling of lipid-mediated cellular activity will need a significant increase in efforts to create and evaluate alternative processes. These efforts shouldn't be limited to mammalian cells, given the increased interest in the occurrence of rafts and raft-like domains in the membranes of yeast, plant cells, and even bacterial cells [4].

References

1. Dietrich C, Yang B, Fujiwara T, et al. Relationship of lipid rafts to transient confinement zones detected by single particle tracking. Biophys J. 2002;82(1):274-84.

Indexed at, Google Scholar, Cross Ref

2. Eggeling C, Ringemann C, Medda R, et al. Direct observation of the nanoscale dynamics of membrane lipids in a living cell. Nature. 2009;457(7233):1159-62.

Indexed at, Google Scholar, Cross Ref

3. Frisz JF, Klitzing HA, Lou K, et al. Sphingolipid domains in the plasma membranes of fibroblasts are not enriched with cholesterol. J Biol Chem. 2013;288(23):16855-61.

Indexed at, Google Scholar, Cross Ref

4. Frisz JF, Lou K, Klitzing HA, et al. Direct chemical evidence for sphingolipid domains in the plasma membranes of fibroblasts. Proceedings of the National Academy of Sciences. 2013;110(8):E613-22.

Indexed at, Google Scholar, Cross Ref