Page last updated: 2024-10-24

lipid transfer activity

Definition

Target type: molecularfunction

Removes a lipid from a membrane or a monolayer lipid particle, transports it through the aqueous phase while protected in a hydrophobic pocket, and brings it to an acceptor membrane or lipid particle. This results in intermembrane transfer of lipids. [GOC:krc, PMID:20823909, PMID:24220498, PMID:25797198]

Lipid transfer activity refers to the ability of a molecule to bind to and transport lipids between different cellular compartments or membranes. Lipids are a diverse group of molecules that include fats, oils, waxes, sterols, and phospholipids. They play essential roles in cell structure, signaling, energy storage, and membrane fluidity. Lipid transfer proteins (LTPs) are responsible for facilitating the movement of lipids within the cell, ensuring proper lipid distribution and function.

The molecular function of lipid transfer activity involves a complex interplay of interactions between the LTP, the lipid substrate, and the target membrane. The process typically begins with the binding of the LTP to the lipid molecule, which is often located within a donor membrane. This binding event is usually highly specific, with LTPs exhibiting preferences for certain types of lipids, such as phospholipids, cholesterol, or fatty acids. Once the lipid is bound, the LTP undergoes a conformational change that allows it to extract the lipid from the donor membrane. This extraction step may involve the formation of a hydrophobic pocket within the LTP structure, which encapsulates the lipid and shields it from the surrounding aqueous environment.

After the lipid is extracted, the LTP translocates to the target membrane, where it releases the lipid. This release process is often facilitated by interactions between the LTP and specific receptors or binding sites on the target membrane. The transfer of lipids between membranes plays a crucial role in various cellular processes, including:

* **Membrane biogenesis and maintenance:** LTPs help to ensure the correct composition and fluidity of cellular membranes by transporting lipids from synthesis sites to their final destination.
* **Signal transduction:** Some LTPs transport lipid signaling molecules, such as cholesterol, between membranes, enabling the transmission of signals within the cell.
* **Lipid storage and mobilization:** LTPs contribute to the regulation of lipid storage in organelles like lipid droplets and the mobilization of lipids for energy production.
* **Apoptosis and other cellular processes:** LTPs can also participate in cellular processes like apoptosis (programmed cell death) by regulating the distribution of lipids involved in membrane remodeling.

The molecular function of lipid transfer activity is essential for maintaining cellular homeostasis and orchestrating a wide range of biological processes. Defects in lipid transfer activity can lead to various pathological conditions, including lipid storage disorders, neurodegenerative diseases, and cardiovascular diseases.
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Proteins (1)

ProteinDefinitionTaxonomy
Alpha-tocopherol transfer proteinAn alpha-tocopherol transfer protein that is encoded in the genome of human. [PRO:DNx, UniProtKB:P49638]Homo sapiens (human)

Compounds (1)

CompoundDefinitionClassesRoles
d-alpha tocopherol(R,R,R)-alpha-tocopherol : An alpha-tocopherol that has R,R,R configuration. The naturally occurring stereoisomer of alpha-tocopherol, it is found particularly in sunflower and olive oils.

tocopherol : A collective name for a group of closely related lipids that contain a chroman-6-ol nucleus substituted at position 2 by a methyl group and by a saturated hydrocarbon chain consisting of three isoprenoid units. They are designated as alpha-, beta-, gamma-, and delta-tocopherol depending on the number and position of additional methyl substituents on the aromatic ring. Tocopherols occur in vegetable oils and vegetable oil products, almost exclusively with R,R,R configuration. Tocotrienols differ from tocopherols only in having three double bonds in the hydrocarbon chain.

vitamin E : Any member of a group of fat-soluble chromanols that exhibit biological activity against vitamin E deficiency. The vitamers in this class consists of a chroman-6-ol core which is substituted at position 2 by a methyl group and (also at position 2) either a saturated or a triply-unsaturated hydrocarbon chain consisting of three isoprenoid units. The major function of vitamin E is to act as a natural antioxidant by scavenging free radicals and molecular oxygen.

Vitamin E: A generic descriptor for all TOCOPHEROLS and TOCOTRIENOLS that exhibit ALPHA-TOCOPHEROL activity. By virtue of the phenolic hydrogen on the 2H-1-benzopyran-6-ol nucleus, these compounds exhibit varying degree of antioxidant activity, depending on the site and number of methyl groups and the type of ISOPRENOIDS.
alpha-tocopherolalgal metabolite;
antiatherogenic agent;
anticoagulant;
antioxidant;
antiviral agent;
EC 2.7.11.13 (protein kinase C) inhibitor;
immunomodulator;
micronutrient;
nutraceutical;
plant metabolite