intermembrane lipid transfer
Definition
Target type: biologicalprocess
The transport of lipids between membranes in which a lipid molecule is transported through an aqueous phase from the outer leaflet of a donor membrane to the outer leaflet of an acceptor membrane. This process does not require metabolic energy and can be either spontaneous or mediated by lipid transfer proteins (LTPs). [GOC:krc, PMID:20823909, PMID:24220498, PMID:25797198]
Intermembrane lipid transfer is a crucial process in cellular function, involving the movement of lipids between different membrane compartments. This intricate process is essential for maintaining membrane integrity, regulating signaling pathways, and facilitating various cellular processes.
The transfer of lipids between membranes can occur through several mechanisms, including:
1. **Vesicular transport:** This involves the budding and fusion of vesicles, small membrane-enclosed compartments that carry lipids from one membrane to another. This process is highly regulated and involves specific proteins that mediate vesicle formation, trafficking, and fusion.
2. **Lipid transfer proteins:** These proteins facilitate the movement of individual lipid molecules across membranes. They bind to lipids on one membrane, diffuse through the aqueous environment, and release the lipids on the other membrane. Examples include phospholipid transfer proteins (PLTPs) and sterol carrier protein 2 (SCP2).
3. **Membrane contact sites:** These are specialized regions where two membranes come into close proximity, allowing for direct lipid exchange. These sites often contain specific proteins that mediate lipid transfer and may involve the formation of transient channels or pores.
The direction of lipid transfer is often dictated by the concentration gradient of the specific lipid and the activity of enzymes that modify lipids. For example, the transfer of cholesterol from the plasma membrane to the endoplasmic reticulum (ER) is driven by the lower concentration of cholesterol in the ER and the activity of enzymes that modify cholesterol in the ER.
Intermembrane lipid transfer is critical for various cellular processes, including:
- **Membrane biogenesis:** Lipid transfer is essential for the formation and maintenance of cellular membranes, ensuring the correct lipid composition for each membrane.
- **Signal transduction:** Lipids play crucial roles in signal transduction pathways, and their transfer between membranes can regulate these pathways.
- **Organelle function:** Lipid transfer is vital for the proper function of various organelles, such as mitochondria, lysosomes, and peroxisomes, by providing the necessary lipids for their biogenesis and activity.
- **Cell growth and differentiation:** Lipid transfer is involved in regulating cell growth, differentiation, and apoptosis.
Dysregulation of intermembrane lipid transfer can lead to various diseases, including atherosclerosis, neurodegenerative disorders, and cancer. Therefore, understanding the mechanisms of intermembrane lipid transfer is crucial for developing therapeutic strategies for these diseases.
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Proteins (2)
| Protein | Definition | Taxonomy |
|---|---|---|
| Microsomal triglyceride transfer protein large subunit | A microsomal triglyceride transfer protein large subunit that is encoded in the genome of human. [PRO:HJD, UniProtKB:P55157] | Homo sapiens (human) |
| Alpha-tocopherol transfer protein | An alpha-tocopherol transfer protein that is encoded in the genome of human. [PRO:DNx, UniProtKB:P49638] | Homo sapiens (human) |
Compounds (6)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| nevirapine | nevirapine : A dipyridodiazepine that is 5,11-dihydro-6H-dipyrido[3,2-b:2',3'-e][1,4]diazepine which is substituted by methyl, oxo, and cyclopropyl groups at positions 4, 6, and 11, respectively. A non-nucleoside reverse transcriptase inhibitor with activity against HIV-1, it is used in combination with other antiretrovirals for the treatment of HIV infection. Nevirapine: A potent, non-nucleoside reverse transcriptase inhibitor used in combination with nucleoside analogues for treatment of HIV INFECTIONS and AIDS. | cyclopropanes; dipyridodiazepine | antiviral drug; HIV-1 reverse transcriptase inhibitor |
| 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-tocopherol | algal metabolite; antiatherogenic agent; anticoagulant; antioxidant; antiviral agent; EC 2.7.11.13 (protein kinase C) inhibitor; immunomodulator; micronutrient; nutraceutical; plant metabolite |
| efavirenz | efavirenz : 1,4-Dihydro-2H-3,1-benzoxazin-2-one substituted at the 4 position by cyclopropylethynyl and trifluoromethyl groups (S configuration) and at the 6 position by chlorine. A non-nucleoside reverse transcriptase inhibitor with activity against HIV, it is used with other antiretrovirals for combination therapy of HIV infection. efavirenz: HIV-1 reverse transcriptase inhibitor | acetylenic compound; benzoxazine; cyclopropanes; organochlorine compound; organofluorine compound | antiviral drug; HIV-1 reverse transcriptase inhibitor |
| bms201038 | BMS201038: an anticholesteremic agent and microsomal triglycide transfer protein inhibitor lomitapide : A member of the class of benzamides obtained by formal condensation of the carboxy group of 4'-(trifluoromethyl)biphenyl-2-carboxylic acid with the primary amino group of 9-[4-(4-aminopiperidin-1-yl)butyl]-N-(2,2,2-trifluoroethyl)-9H-fluorene-9-carboxamide. Used (as its mesylate salt) as a complement to a low-fat diet and other lipid-lowering treatments in patients with homozygous familial hypercholesterolemia. | (trifluoromethyl)benzenes; benzamides; fluorenes; piperidines | anticholesteremic drug; MTP inhibitor |
| dirlotapide | dirlotapide: structure in first source | ||
| jnj-31020028 |