Everything about Ether Lipid totally explained
Ether lipids are
lipids in which one or more of the
carbon atoms on
glycerol is bonded to an
alkyl chain via an
ether linkage, as opposed to the usual
ester linkage.
Types
Ether lipids are called
plasmalogens (1-O-1'-alkenyl-2-acylglycerophospholipids) if these are
glycerol-containing
phospholipids with an unsaturated
O-(1-alkenyl) (
vinyl ether) group at the first position on the glycerol chain.
Platelet-activating factor is an ether lipid which has an
acetyl group instead of an
acyl chain at the second position (SN-2).
Biosynthesis
The formation of the ether bond in mammals requires two enzymes, dihydoxyacetonephosphate acyltransferase (DHAPAT) and alkyldihydroxyacetonephosphate synthase (ADAPS), that reside in the
peroxisome. Accordingly, peroxisomal defects often lead to impairment of ether-lipid production.
Functions
Structural
Plasmalogens as well as some 1-O-alkyl lipids are ubiquitous and sometimes major parts of the
cell membranes in
mammals and
anaerobic bacteria. In archaea, ether lipids are the major polar lipids in the cell envelope and their abundance is one of the major characteristics that separate this group of
prokaryotes from the
bacteria. In these cells, diphytanylglycerolipids or bipolar macrocyclic tetraethers can form
covalently linked 'bilayers'.
Second messenger
Differences between the
catabolism of ether glycerophospholipids by specific
phospholipases
enzymes might be involved in the generation of lipid
second messenger systems such as
prostaglandins and
arachidonic acid that are important in signal transduction. Ether lipids can also act directly in cell signaling, as the
platelet-activating factor is an ether lipid signaling molecule that's involved in
leukocyte function in the mammalian
immune system.
Antioxidant
Another possible function of the plasmalogen ether lipids is as
antioxidants, as protective effects against
oxidative stress have been demonstrated in
cell culture and these lipids might therefore play a role in serum
lipoprotein metabolism. This antioxidant activity comes from the enol ether double bond being targeted by a variety of
reactive oxygen species.
Synthetic ether lipid analogs
Synthetic ether lipid analogs have
cytostatic and cytotoxic properties, probably by disrupting membrane structure and acting as
inhibitors of enzymes within signal transmission pathways, such as
protein kinase C and
phospholipase C.
A toxic ether lipid analogue
miltefosine has recently been introduced as an oral treatment for the tropical disease
leishmaniasis, which is caused by
leishmania, a
protozoal parasite with a particularly high ether lipid content in its membranes.
Further Information
Get more info on 'Ether Lipid'.
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