Table Of ContentBiochemistry of Lipids,
Lipoproteins and
Membranes
Sixth Edition
Edited by
Neale D. Ridgway, Ph.D.
Departments of Pediatrics and Biochemistry & Molecular Biology
Dalhousie University
Halifax, Nova Scotia, Canada
Roger S. McLeod, Ph.D.
Department of Biochemistry & Molecular Biology
Dalhousie University
Halifax, Nova Scotia, Canada
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Contributors
Khosrow Adeli The Hospital for Sick Children, University of Toronto, Toronto, ON,
Canada
Mikhail Bogdanov Department of Biochemistry and Molecular Biology, University
of Texas–Houston, Medical School, Houston, TX, USA
Laura M. Bond Department of Biochemistry, University of Wisconsin-Madison,
Madison, WI, USA
Andrew J. Brown School of Biotechnology and Biomolecular Sciences, The
University of New South Wales (UNSW Australia), Sydney, NSW, Australia
H. Alex Brown Department of Pharmacology, Vanderbilt University School of Medicine,
Nashville, TN, USA; Department of Biochemistry and The Vanderbilt Institute of
Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
Alan Daugherty Saha Cardiovascular Research Center, University of Kentucky,
Lexington, KY, USA
Paul A. Dawson Division of Pediatric Gastroenterology, Hepatology and Nutrition,
Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA, USA
Fang Ding Institute of Animal Genetics and Breeding, College of Animal Science and
Technology, Sichuan Agricultural University, Wenjiang, Sichuan, PR, China
William Dowhan Department of Biochemistry and Molecular Biology, University
of Texas–Houston, Medical School, Houston, TX, USA
Sarah Farr The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
Gordon A. Francis Department of Medicine, Centre for Heart Lung Innovation,
University of British Columbia, Vancouver, BC, Canada
Anthony H. Futerman Department of Biological Chemistry, Weizmann Institute
of Science, Rehovot, Israel
Murray W. Huff Departments of Medicine and Biochemistry, Robarts Research
Institute, The University of Western Ontario, London, ON, Canada
Pavlina T. Ivanova Department of Pharmacology, Vanderbilt University School of
Medicine, Nashville, TN, USA
Richard Lehner Group on Molecular and Cell Biology of Lipids, University
of Alberta, Edmonton, AB, Canada; Departments of Pediatrics and Cell Biology,
University of Alberta, Edmonton, AB, Canada
Gary F. Lewis University Health Network, University of Toronto, Toronto, ON, Canada
xix
xx Contributors
Hong Lu Saha Cardiovascular Research Center, University of Kentucky, Lexington,
KY, USA
Frederick R. Maxfield Department of Biochemistry, Weill Cornell Medical College,
New York, NY, USA
Jeff G. McDonald Department of Molecular Genetics, UT Southwestern Medical
Center, Dallas, TX, USA
Roger S. McLeod Department of Biochemistry & Molecular Biology, Dalhousie
University, Halifax, NS, Canada
Anant K. Menon Department of Biochemistry, Weill Cornell Medical College,
New York, NY, USA
Eugenia Mileykovskaya Department of Biochemistry and Molecular Biology,
University of Texas–Houston, Medical School, Houston, TX, USA
Makoto Miyazaki Department of Medicine, Division of Renal Diseases and
Hypertension, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
Robert C. Murphy Department of Pharmacology, University of Colorado-Denver,
Aurora, CO, USA
James M. Ntambi Department of Biochemistry, University of Wisconsin-Madison,
Madison, WI, USA; Department of Nutritional Science, University of Wisconsin-
Madison, Madison, WI, USA
Lucas M. O’Neill Department of Biochemistry, University of Wisconsin-Madison,
Madison, WI, USA
Ariel D. Quiroga Group on Molecular and Cell Biology of Lipids, University of
Alberta, Edmonton, AB, Canada; Institute of Experimental Physiology (IFISE-
CONICET), Faculty of Biochemical and Pharmacological Sciences, National
University of Rosario, Suipacha, Rosario, Argentina
Marilyn D. Resh Cell Biology Program, Memorial Sloan Kettering Cancer Center,
New York, NY, USA
Neale D. Ridgway Departments of Pediatrics and Biochemistry & Molecular Biology,
Dalhousie University, Halifax, NS, Canada
Charles O. Rock Department of Infectious Diseases, St. Jude Children’s Research
Hospital, Memphis, TN, USA
Katherine M. Schmid Department of Biology, Butler University, Indianapolis, IN, USA
Wolfgang J. Schneider Department of Medical Biochemistry, Medical University of
Vienna, Vienna, Austria
Laura J. Sharpe School of Biotechnology and Biomolecular Sciences, The University
of New South Wales (UNSW Australia), Sydney, NSW, Australia
William L. Smith Department of Biological Chemistry, University of Michigan
Medical School, Ann Arbor, MI, USA
Robert V. Stahelin Department of Biochemistry & Molecular Biology, Indiana
University School of Medicine-South Bend, South Bend, IN, USA; Department of
Chemistry & Biochemistry, University of Notre Dame, Notre Dame, IN, USA
Contributors xxi
Jennifer Taher The Hospital for Sick Children, University of Toronto, Toronto, ON,
Canada
Changting Xiao University Health Network, University of Toronto, Toronto, ON, Canada
Zemin Yao Department of Biochemistry, Microbiology and Immunology, University
of Ottawa, Ottawa, ON, Canada
Yong-Mei Zhang Department of Biochemistry and Molecular Biology, Medical
University of South Carolina, Charleston, SC, USA
Preface
This represents the sixth edition of the textbook first edited by Drs. Dennis and
Jean Vance in 1985. In taking on the editorship, we are revising the textbook
that we used as an essential resource early in our academic careers. With this in
mind we have strived to assemble a text that will inspire students to embrace the
challenges of the future in lipid, lipoprotein and membrane biology.
Since the last edition that appeared in 2008 there have been remarkable
advances in lipid and membrane biology in terms of identification of funda-
mental metabolic processes and their relationship to a broad spectrum of human
diseases. The authors of this edition are at the forefront of these discoveries,
and have provided chapters with a basic knowledge component coupled with
unique insights into their respective fields of research. This edition also has a
more defined focus on the impact on new technologies and relevance to chronic
disease with a view to future studies of lipid metabolism. As with previous edi-
tions, the content is easily accessible to a broad spectrum of learners with a
basic understanding of biochemistry and metabolism. The text also serves as a
gateway to further exploration of topics, and provides a bridge between basic
concepts and the current research literature. Thus undergraduate and graduate
students will find this book to be an essential resource for course and research-
related studies, while experienced researchers can use it as a reference guide to
the lipid field.
All of the chapters have been revised from the fifth edition and new authors
have taken on the task for many. We asked the authors to resist the temptation
to be comprehensive; that we were not seeking to assemble a compendium of
reviews. In addition, we limited the number of citations, attempting to glean
classic and exceptional recent studies in each area. We are grateful that all the
authors have complied. This edition of the book has full-color figures embedded
in the text and standardized tables, which add visual appeal and clarity.
The contributors and editors assume full responsibility for the content and
would appreciate any and all feedback for refinement of future editions.
Neale D. Ridgway and Roger S. McLeod
Halifax, Nova Scotia, Canada
June 2015
xxiii
Chapter 1
Functional Roles of Lipids
in Membranes
William Dowhan, Mikhail Bogdanov, Eugenia Mileykovskaya
Department of Biochemistry and Molecular Biology, University of Texas–Houston, Medical
School, Houston, TX, USA
ABBREVIATIONS
CL Cardiolipin
DAG Diacylglycerol
EMD Extramembrane domain
GlcDAG Monoglucosyl diacylglycerol
GlcGlcDAG DIglucosyl diacylglycerol
NAO 10-N-nonyl acridine orange
PA Phosphatidic acid
PC Phosphatidylcholine
PE Phosphatidylethanolamine
PG Phosphatidylglycerol
PI Phosphatidylinositol
PS Phosphatidylserine
T Midpoint temperature
m
TMD Transmembrane domain
1. INTRODUCTION AND OVERVIEW
Lipids as a class of molecules display a wide diversity in structure and biological
function. A primary role of lipids is to form the membrane bilayer permeability
barrier of cells and organelles (Figure 1). Glycerophospholipids (termed phos-
pholipids hereafter) make up about 75% of total membrane lipids of prokaryotic
and eukaryotic cells, but other lipids are important components. Table 1 shows
the major lipids found in the membranes of various cells and organelles but does
not include the minor lipids, many of which are functionally important. Sterols
are present in all eukaryotic cells and in a few bacterial membranes. The major
sterol of mammalian cells is cholesterol whereas yeast contain ergosterol. Bac-
teria do not make sterols but some species incorporate sterols from the growth
medium. Interestingly Drosophila also must acquire cholesterol from exogenous
sources. The ceramide-based sphingolipids are present in the membranes of all
eukaryotes. Neutral diacylglycerol (DAG) glycans are major membrane-forming
Biochemistry of Lipids, Lipoproteins and Membranes. http://dx.doi.org/10.1016/B978-0-444-63438-2.00001-8
Copyright © 2016 Elsevier B.V. All rights reserved. 1
2 Biochemistry of Lipids, Lipoproteins and Membranes
GPI-anchored
protein
Carbohydrate
Exterior
Glycoprotein
Cholesterol
Hydrophilic
region
Hydrophobic
region
Hydrophilic
region
Integral
protein
Peripheral Phospholipid
protein
Interior
FIGURE 1 Model for membrane structure. This model of the plasma membrane of a eukaryotic
cell is an adaptation of the original model proposed by Singer and Nicholson (1972). The phospho-
lipid bilayer is shown with integral membrane proteins largely containing α-helical transmembrane
domains (TMDs). Peripheral membrane proteins associate either with the lipid surface or with other
membrane proteins. Lipid rafts (dark green head groups) are enriched in cholesterol and contain a
PI glycan-linked (GPI) protein. The purple head groups depict lipids in close association with protein.
The irregular surface and wavy acyl chains denote the fluid nature of the bilayer.
components in many Gram-positive bacteria and in the membranes of plants,
while Gram-negative bacteria utilise a saccharolipid (Lipid A) as a major
structural component of the outer leaflet of the outer membrane. The variety
of hydrophobic domains of lipids results in additional diversity. In eukaryotes
and eubacteria these domains are saturated and unsaturated fatty acids or lesser
amounts of fatty alcohols; many Gram-positive bacteria also contain branched
chain fatty acids. Instead of esterified fatty acids, Archaea contain long chain
reduced polyisoprene moieties in ether linkage to glycerol. Such hydrophobic
domains are highly resistant to the harsh environment of these organisms. Fur-
ther stability of the lipid bilayer of Archaea comes from many of the hydro-
carbon chains spanning the membrane with covalently linked head groups at
each end. If one considers a simple organism such as Escherichia coli with three
major phospholipids and several different fatty acids along with many minor pre-
cursors and modified lipid products, the number of individual phospholipid spe-
cies ranges in the hundreds. In more complex eukaryotic organisms with greater
diversity in both phospholipids and fatty acids, the number of individual species
is in the thousands. Sphingolipids also show a similar degree of diversity and
Functional Roles of Lipids in Membranes Chapter | 1 3
TABLE 1 Lipid Composition of Various Biological Membranes
Mitochondriac
CHO Endoplasmic Escherichia
Lipid Erythrocytea Cellsb Outer Inner Reticulumd colie
Choles 25 – N.D. N.D. 20 N.D.
terol
PE 18 21 33 24 21 75
PC 19 51 46 38 46 N.D.
Sphingo 18 9 – – 9 N.D.
myelin
PS 9 7 1 4 2 <1
PG 0 1 N.D. N.D. – 20
CL 0 2.3 6 16 – 5
PI 1 8 10 16 2 N.D.
Glyco 10 – – – – N.D.
sphingo
lipid
PA – 1 4 2 – <2
The data are expressed as mol% of total lipid. N.D. indicates not detected and blank indicates not
analysed.
aHuman (Tanford, 1980).
bChinese hamster cells (Ohtsuka et al., 1993).
cSaccharomyces cerevisiae inner and outer mitochondrial membrane (Zinser et al., 1991).
dMurine L cells (Murphy et al., 2000).
eInner and outer membrane excluding Lipid A (Raetz, 1990).
when added to the steroids the size of the eukaryotic lipidome dwarfs that of the
proteome.
Lipids provide the solvent within which integral membrane proteins (those
whose transmembrane domains (TMDs) span the bilayer) are integrated.
Peripheral proteins also interact with the membrane surface and are even found
partially inserted into the lipid bilayer. These amphitropic proteins are found
in the aqueous compartments of cells and interact with the membrane surface in
a reversible manner. The lipid bilayer provides a rich and varied environment
for proteins, which includes a highly hydrophobic interior bounded by the
hydrophilic and/or charged lipid head groups. The latter organises water and
counterions in a manner significantly differently from that of the cell aqueous
phase, which imparts distinct properties to the aqueous layer in close contact
with the membrane surface. Each lipid molecular class is made up of a wide
spectrum of chemical and structural variants, which as an ensemble determine
membrane fluidity, lateral pressure, permeability and surface charge. The lipid
and protein components of the membrane are not held together by covalent
4 Biochemistry of Lipids, Lipoproteins and Membranes
interactions and therefore are in dynamic equilibrium undergoing transient
interactions organised into the supermolecular structure of the lipid bilayer.
In this chapter, the diversity in structure, chemical properties and physical
properties of lipids will be outlined. The various genetic approaches available
for studying lipid function in vivo will be summarised. Finally, how the physi-
cal and chemical properties of lipids relate to their multiple functions in living
systems will be reviewed to provide a molecular basis for the diversity of lipid
structures in natural membranes. Due to space limitations, recent review articles
and research articles, which contain the primary background references sup-
porting the summaries in the text, are cited.
2. DIVERSITY IN LIPID STRUCTURE
Lipids are defined as those biological molecules readily soluble in organic
solvents such as chloroform, ether or toluene. However, many peptides and
some very hydrophobic proteins are soluble in organic solvents, and lipids
with large hydrophilic domains such as saccharolipids are not soluble in these
solvents. Here we will consider those lipids that contribute significantly to
membrane structure or have a role in determining protein structure or func-
tion. The LIPID MAPS consortium (http://www.lipidmaps.org) in the United
States, Lipid Bank (http://www.lipidbank.jp) in Japan and the LipidomicNet
(http://www.lipidomicnet.org) in Europe have cooperated to devise classifica-
tion systems, methodology and forums for the benefit of researchers.
2.1 Glycerolipids
The DAG backbone in eubacteria and eukaryotes is sn-3-glycerol (l-glyc-
erol) esterified at the 1- and 2-position with long chain fatty acids (Figure 2)
(Chapters 3 and 7). In Archae (Figure 3) sn-1-glycerol (d-glycerol) forms the
backbone and the hydrophobic domain is composed of phytanyl (saturated
isoprenyl) groups in ether linkage at the 2- and 3-positions (an archaeol)
(Koga and Morii, 2007). In addition, two sn-1-glycerol groups are connected
in ether linkage by two biphytanyl groups (dibiphytanyldiglycerophospha-
tetetraether) to form a covalently linked bilayer. Some eubacteria (mainly
hyperthermophiles) have dialkyl (long chain alcohols in ether linkage) phos-
pholipids and similar ether linkages are found in the plasmalogens of eukary-
otes. The head groups of the phospholipids (boxed area of Figure 2) extend
the diversity of lipids defining phosphatidic acid (PA, with OH), phosphati-
dylcholine (PC), phosphatidylserine (PS), phosphatidylglycerol (PG), phos-
phatidylinositol (PI) and cardiolipin (CL). Archae analogues exist with head
groups of glycerol and glyceromethylphosphate as well as all of the above
except PC. Archae also have neutral glycan lipid derivatives in which mono-
and disaccharides (glucose or galactose) are directly linked to the sn-1 posi-
tion of archaeol (Figure 3). Plants (mainly in the thylakoid membrane) and
many Gram-positive bacteria also have high levels of neutral DAG glycans
