Retrograde lipid traffic in yeast: identification of two distinct pathways for internalization of fluorescent-labeled phosphatidylcholine from the plasma membrane
Retrograde lipid traffic in yeast: identification of two distinct pathways for internalization of fluorescent-labeled phosphatidylcholine from the plasma membrane
复制标题
酵母中的逆行脂质运输：鉴定荧光标记的磷脂酰胆碱从质膜内化的两种不同途径
作者：
L S Kean;R S Fuller;J W Nichols
Digital, video-enhanced fluorescence microscopy and spectrofluorometry were used to follow the internalization into the yeast Saccharomyces cerevisiae of phosphatidylcholine molecules labeled on one acyl chain with the fluorescent probe 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD). Two pathways were found: (1) transport by endocytosis to the vacuole and (2) transport by a non-endocytic pathway to the nuclear envelope and mitochondria. The endocytic pathway was inhibited at low temperature (< 2 degrees C) and by ATP depletion. Mutations in secretory (SEC) genes that are necessary for membrane traffic through the secretory pathway (including SEC1, SEC2, SEC4, SEC6, SEC7, SEC12, SEC14, SEC17, SEC18, and SEC21) almost completely blocked endocytic uptake. In contrast, mutations in the SEC63, SEC65, or SEC11 genes, required for translocation of nascent secretory polypeptides into the ER or signal peptide processing in the ER, only slightly reduced endocytic uptake. Phospholipid endocytosis was also independent of the gene encoding the clathrin heavy chain, CHC1. The correlation of biochemical analysis with fluorescence microscopy indicated that the fluorescent phosphatidylcholine was degraded in the vacuole and that degradation was, at least in part, dependent on the vacuolar proteolytic cascade. The non-endocytic route functioned with a lower cellular energy charge (ATP levels 80% reduced) and was largely independent of the SEC genes. Non-endocytic transport of NBD-phosphatidylcholine to the nuclear envelope and mitochondria was inhibited by pretreatment of cells with the sulfhydryl reagents N-ethylmaleimide and p- chloromercuribenzenesulfonic acid, suggesting the existence of protein- mediated transmembrane transfer (flip-flop) of phosphatidylcholine across the yeast plasma membrane. These data establish a link between lipid movement during secretion and endocytosis in yeast and suggest that phospholipids may also gain access to intracellular organelles through non-endocytic, protein-mediated events.
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网格蛋白在酵母高尔基复合体液泡蛋白分类中的作用。
DOI：
10.1002/j.1460-2075.1992.tb05348.x
发表时间：
1992
期刊：
The EMBO journal
影响因子：
--
作者：
Seeger,M;Payne,GS
通讯作者：
Payne,GS
DOI：
--
发表时间：
1985-01
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
R. Sleight;R. Pagano
通讯作者：
R. Sleight;R. Pagano
DOI：
10.1002/j.1460-2075.1989.tb03614.x
发表时间：
1989-07
期刊：
The EMBO Journal
影响因子：
--
作者：
J. Rothman;I. Howald;T. Stevens
通讯作者：
J. Rothman;I. Howald;T. Stevens
影响因子：
2.9
作者：
STRUCK, DK;HOEKSTRA, D;PAGANO, RE
通讯作者：
PAGANO, RE
磷脂酰丝氨酸和磷脂酰乙醇胺的荧光类似物在培养细胞质膜上的跨双层运动。
DOI：
--
发表时间：
1987
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Martin,OC;Pagano,RE
通讯作者：
Pagano,RE