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Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is a phospholipid acyltransferase that promotes phospholipid synthesis and plasma membrane reconstruction. Exosomes play an important role in tumor metastasis. The release and uptake of exosomes are key steps of their functions and depend on plasma membrane fusion and plasma membrane receptors, respectively. The purpose of this study was to explore whether LPCAT1-induced plasma membrane remodeling would change the secretion and uptake behavior of exosomes in tumor cells. We first confirmed the abnormally high expression of LPCAT1 in colorectal cancer cells by quantitative real-time PCR (qPCR) and Western blot analysis. Then, SW620 cells were used as exosome source cells, and SW480 cells were used as exosome receiver cells. Exosomes from SW620 cells could effectively promote the migration of SW480 cells. When LPCAT1 expression was reduced via siRNA knockdown in the source cells, the secretion of exosomes was downregulated, thus weakening the pro-migratory effects of exosomes on target cells. Conversely, when LPCAT1 was knocked down in target cells, the uptake of exosomes in target cells also decreased sharply. These results undoubtedly revealed that LPCAT1 is functionally associated with the release and internalization of exosomes in colorectal cancer cells and could affect the paracrine effects of exosomes, preliminarily extending the classical metabolic function of LPCAT1 to exosome-related pathways.  相似文献   
2.
Acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT, EC 2.3.1.23) catalyzes acylation of lysophosphatidylcholine (lysoPtdCho) to produce phosphatidylcholine (PtdCho), the main phospholipid in cellular membranes. This reaction is a key component of the acyl-editing process, involving recycling of the fatty acids (FA) mainly at the sn-2 position of PtdCho. Growing evidences indicate that the LPCAT reaction controls the direct entry of newly synthesized FA into PtdCho and, at least in some plant species, it has an important impact on the synthesis and composition of triacylglycerols. Here we describe the molecular characterization of the single LPCAT gene found in the genome of Ricinus communis (RcLPCAT) that is homologous to LPCAT genes of the MBOAT family previously described in Arabidopsis and Brassica. RcLPCAT is ubiquitously expressed in all organs of the castor plant. Biochemical properties have been studied by heterologous expression of RcLPCAT in the ale1 yeast mutant, defective in lysophospholipid acyltransferase activity. RcLPCAT preferentially acylates lysoPtdCho against other lysophospholipids (lysoPL) and does not discriminates the acyl chain in the acceptor, displaying a strong activity with alkyl lysoPL. Regarding the acyl-CoA donor, RcLPCAT uses monounsaturated fatty acid thioesters, such as oleoyl-CoA (18:1-CoA), as preferred donors, while it has a low activity with saturated fatty acids and shows a poor utilization of ricinoleoyl-CoA (18:1-OH-CoA). These characteristics are discussed in terms of a possible role of RcLPCAT in regulating the entry of FA into PtdCho and the exclusion from the membranes of the hydroxylated FA.  相似文献   
3.
Recent results have suggested that plant lysophosphatidylcholine:acyl‐coenzyme A acyltransferases (LPCATs) can operate in reverse in vivo and thereby catalyse an acyl exchange between the acyl‐coenzyme A (CoA) pool and the phosphatidylcholine. We have investigated the abilities of Arabidopsis AtLPCAT2, Arabidopsis lysophosphatidylethanolamine acyltransferase (LPEAT2), S. cerevisiae lysophospholipid acyltransferase (Ale1) and S. cerevisiae lysophosphatidic acid acyltransferase (SLC1) to acylate lysoPtdCho, lysoPtdEtn and lysoPtdOH and act reversibly on the products of the acylation; the PtdCho, PtdEtn and PtdOH. The tested LPLATs were expressed in an S. cervisiaeale1 strain and enzyme activities were assessed in assays using microsomal preparations of the different transformants. The results show that, despite high activity towards lysoPtdCho, lysoPtdEtn and lysoPtdOH by the ALE1, its capacities to operate reversibly on the products of the acylation were very low. Slc1 readily acylated lysoPtdOH, lysoPtdCho and lysoPtdEtn but showed no reversibility towards PtdCho, very little reversibility towards PtdEtn and very high reversibility towards PtdOH. LPEAT2 showed the highest levels of reversibility towards PtdCho and PtdEtn of all LPLATs tested but low ability to operate reversibly on PtdOH. AtLPCAT2 showed good reversible activity towards PtdCho and PtdEtn and very low reversibility towards PtdOH. Thus, it appears that some of the LPLATs have developed properties that, to a much higher degree than other LPLATs, promote the reverse reaction during the same assay conditions and with the same phospholipid. The results also show that the capacity of reversibility can be specific for a particular phospholipid, albeit the lysophospholipid derivatives of other phospholipids serve as good acyl acceptors for the forward reaction of the enzyme.  相似文献   
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The search of the Phaeodactylum tricornutum genome database revealed the existence of six genes potentially encoding lysophospholipid acyltransferases. One of these genes, Phatr3_J20460, after introduction to yeast ale1 mutant disrupted in the LPCAT gene, produced a very active acyl-CoA:lysophosphatidylcholine (LPCAT) enzyme. Using in vitro assays applying different radioactive and non-radioactive substrates and microsomal fractions from such yeast, we have characterized the biochemical properties and substrate specificities of this PtLPCAT1. We have found that the substrate specificity of this enzyme indicates that it can completely supply phosphatidylcholine (PC) with all fatty acids connected with a biosynthetic pathway of very long-chain polyunsaturated fatty acids (VLC-PUFAs) used further for the desaturation process. Additionally, we have shown that biochemical properties of the PtLPCAT1 in comparison to plant LPCATs are in some cases similar (such as the dependency of its activity on pH value), differ moderately (such as in response to temperature changes), or express completely different properties (such as in reaction to calcium and magnesium ions or toward some acyl-CoA with 20C polyunsaturated fatty acids). Moreover, the obtained results suggest that cloned “Phatr3_J20460” gene can be useful in oilseeds plant engineering toward efficient production of VLC-PUFA as LPCAT it encodes can (contrary to plant LPCATs) introduce 20:4-CoA (n-3) to PC for further desaturation to 20:5 (EPA, eicosapentaenoic acid).  相似文献   
6.
Kazachkov M  Chen Q  Wang L  Zou J 《Lipids》2008,43(10):895-902
An important enzyme involved in phospholipid turnover is the acyl-CoA: lysophosphatidylcholine acyltransferase (LPCAT). Here, we report characterization of a newly discovered human LPCAT (LPCAT3), which has distinct substrate preferences strikingly consistent with a role in phosphatidylcholine (PtdCho) remodeling and modulating fatty acid composition of PtdCho. LPCAT3 prefers lysophosphatidylcholine (lysoPtdCho) with saturated fatty acid at the sn-1 position and exhibits acyl donor preference towards linoleoyl-CoA and arachidonoyl-CoA. Furthermore, LPCAT3 is active in mediating 1-O-alkyl-sn-glycero-3-phosphocholine acylation with long chain fatty acyl-CoAs to generate 1-O-alkyl-phosphatidylcholine, another very important constitute of mammalian membrane systems. These properties are precisely the known attributes of LPCAT previously ascribed to the isoform involved in Lands' cycle, and thus strongly suggest that LPCAT3 is involved in phospholipids remodeling to achieve appropriate membrane lipid fatty acid composition.  相似文献   
7.
Cellular membranes contain glycerophospholipids, which have important structural and functional roles in cells. Glycerophospholipids are first formed in the de novo pathway (Kennedy pathway) and are matured in the remodeling pathway (Lands’ cycle). Recently, lysophospholipid acyltransferases functioning in Lands’ cycle were identified and characterized. Several enzymes involved in glycerophospholipid biosynthesis have been reported to have important roles in adipocytes. However, the role of Lands’ cycle in adipogenesis has not yet been reported. Using C3H10T1/2, a cell line capable of differentiating to adipocyte-like cells in vitro, changes of lysophospholipid acyltransferase activities were investigated. Lysophosphatidylcholine acyltransferase (LPCAT), lysophosphatidylethanolamine acyltransferase (LPEAT) and lysophosphatidylserine acyltransferase (LPSAT) activities were enhanced, especially with 18:2-CoA and 20:4-CoA as donors. Correspondingly, mRNA expression of LPCAT3, which possesses LPCAT, LPEAT and LPSAT activities with high specificity for 18:2- and 20:4-CoA, was upregulated during adipogenesis. Analysis of acyl-chain compositions of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) showed a change in their profiles between preadipocytes and adipocytes, including an increase in the percentage of arachidonic acid-containing phospholipids. These changes are consistent with the activities of LPCAT3. Therefore, it is possible that enhanced phospholipid remodeling by LPCAT3 may be associated with adipocyte differentiation.  相似文献   
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