With the realization of dynamic protein distribution in the cell membrane, the fluid mosaic model was introduced and has become the most accepted model until now. Then, based on investigations with ultrathin section electron microscopy, an improved unit membrane model was developed, indicating the presence of a lipid bilayer with a thickness of 3.5 nm, in addition to proteins.
The structure of the cell membrane was initially viewed as a sandwich that consists of protein-lipid-protein. Although different cell membrane models have been introduced over the past century, we are still far from fully understanding this important cellular component –. The cell membrane, also termed the plasma membrane, plays a crucial role in various cellular activities, such as signal transduction, membrane trafficking, as well as energy conversion –. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. 31330082 to JJ) and the “100 Talent Program” of CAS (to HW). 2011CB933600 to HW, 2012CB519001 to SJ), NSFC - National Natural Science Foundation of China (Grant no. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.įunding: This work was supported by MOST - Ministry of Science and Technology of China (Grant no. Received: NovemAccepted: FebruPublished: May 7, 2014Ĭopyright: © 2014 Zhao et al.
Weiss, University of the Witwatersrand, South Africa (2014) Studying the Nucleated Mammalian Cell Membrane by Single Molecule Approaches. Based on these observations, we proposed a Protein Layer-Lipid-Protein Island (PLLPI) model, to provide a better understanding of cell membrane structure, membrane trafficking and viral fusion mechanisms.Ĭitation: Zhao W, Tian Y, Cai M, Wang F, Wu J, Gao J, et al. Using a combination of single-molecule techniques, including atomic force microscopy (AFM), single molecule force spectroscopy (SMFS) and stochastic optical reconstruction microscopy (STORM), to study the structure of nucleated cell membranes, we found that (1) proteins at the ectoplasmic side of the cell membrane form a dense protein layer (4 nm) on top of a lipid bilayer (2) proteins aggregate to form islands evenly dispersed at the cytoplasmic side of the cell membrane with a height of about 10–12 nm (3) cholesterol-enriched domains exist within the cell membrane (4) carbohydrates stay in microdomains at the ectoplasmic side and (5) exposed amino groups are asymmetrically distributed on both sides.
The cell membrane plays a key role in compartmentalization, nutrient transportation and signal transduction, while the pattern of protein distribution at both cytoplasmic and ectoplasmic sides of the cell membrane remains elusive.
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