共查询到20条相似文献，搜索用时 31 毫秒
1.
脂筏在病原微生物侵入细胞中的作用 总被引：1，自引：0，他引：1
研究表明,许多不同类型和种属的病原微生物利用脂筏结构介导进入细胞,完成转运和复制。对脂筏在病原微生物侵入细胞中的作用进行了研究,有助于探索新的抗病原微生物进入细胞的途径。 相似文献
2.
del Pozo MA Alderson NB Kiosses WB Chiang HH Anderson RG Schwartz MA 《Science (New York, N.Y.)》2004,303(5659):839-842
Translocation of the small GTP-binding protein Rac1 to the cell plasma membrane is essential for activating downstream effectors and requires integrin-mediated adhesion of cells to extracellular matrix. We report that active Rac1 binds preferentially to low-density, cholesterol-rich membranes, and specificity is determined at least in part by membrane lipids. Cell detachment triggered internalization of plasma membrane cholesterol and lipid raft markers. Preventing internalization maintained Rac1 membrane targeting and effector activation in nonadherent cells. Regulation of lipid rafts by integrin signals may regulate the location of membrane domains such as lipid rafts and thereby control domain-specific signaling events in anchorage-dependent cells. 相似文献
3.
A role for lipid shells in targeting proteins to caveolae,rafts, and other lipid domains 总被引：2，自引：0，他引：2
The surface membrane of cells is studded with morphologically distinct regions, or domains, like microvilli, cell-cell junctions, and coated pits. Each of these domains is specialized for a particular function, such as nutrient absorption, cell-cell communication, and endocytosis. Lipid domains, which include caveolae and rafts, are one of the least understood membrane domains. These domains are high in cholesterol and sphingolipids, have a light buoyant density, and function in both endocytosis and cell signaling. A major mystery, however, is how resident molecules are targeted to lipid domains. Here, we propose that the molecular address for proteins targeted to lipid domains is a lipid shell. 相似文献
4.
B M Phelps P Primakoff D E Koppel M G Low D G Myles 《Science (New York, N.Y.)》1988,240(4860):1780-1782
The rate of lateral diffusion of integral membrane proteins is constrained in cells, but the constraining factors for most membrane proteins have not been defined. PH-20, a sperm surface protein involved in sperm-egg adhesion, was shown to be anchored in the plasma membrane by attachment to the lipid phosphatidylinositol and to have a diffusion rate that is highly restricted on testicular sperm, being more than a thousand times slower than lipid diffusion. These results support the hypothesis that lateral mobility of a membrane protein can be regulated exclusively by interactions of its ectodomain. 相似文献
5.
脂筏是细胞膜上富含胆固醇和鞘脂的区域,近几年来的研究发现脂筏能介导某些细菌和病毒侵入细胞,同时也在病毒生命周期的许多阶段发挥着关键作用。有关脂筏的研究主要集中在脂筏介导病原微生物侵染细胞及其在某些微生物的生命周期中所起的作用,对此进行了综述。 相似文献
6.
Dissection of the mammalian midbody proteome reveals conserved cytokinesis mechanisms 总被引：1，自引：0，他引：1
Cytokinesis is the essential process that partitions cellular contents into daughter cells. To identify and characterize cytokinesis proteins rapidly, we used a functional proteomic and comparative genomic strategy. Midbodies were isolated from mammalian cells, proteins were identified by multidimensional protein identification technology (MudPIT), and protein function was assessed in Caenorhabditis elegans. Of 172 homologs disrupted by RNA interference, 58% displayed defects in cleavage furrow formation or completion, or germline cytokinesis. Functional dissection of the midbody demonstrated the importance of lipid rafts and vesicle trafficking pathways in cytokinesis, and the utilization of common membrane cytoskeletal components in diverse morphogenetic events in the cleavage furrow, the germline, and neurons. 相似文献
7.
Many plasma membrane proteins, including Thy-1, are anchored by a carboxyl terminal glycophospholipid. This unit is absent from the Thy-1 of several lymphoma mutants that synthesize the Thy-1 polypeptide but fail to express it at the cell surface. Recessive mutants of complementation groups A to C, E, and F contain Thy-1 mRNA of normal size, which suggests that their Thy-1 polypeptide is normal. To identify possible metabolic lesions, each mutant was grown with various supplements. The class F and B mutants exhibited a reversible induction of surface lipid anchored Thy-1 when grown with the aminoglycoside G418. Other aminoglycosides, sugars, and ethanolamine were inactive. These unexpected observations are discussed in the context of lipid anchor biosynthesis. 相似文献
8.
An elaborate vesicle transport system supports the active exchange of membranes and protein cargo between the plasma membrane and the trans-Golgi network. Many observations suggest that highly conserved mechanisms are used in vesicle formation and scission. Such similarity is found both at the level of the receptor-ligand sequestration process that uses clathrin and associated polymeric and monomeric adaptor proteins, and in the machinery used to deform and vesiculate lipid membranes. 相似文献
9.
Membrane structure: some general principles 总被引：55，自引：0，他引：55
M S Bretscher 《Science (New York, N.Y.)》1973,181(100):622-629
The arrangement of lipids and some proteins in the erythrocyte membrane has been discussed. The conclusions from this are listed here as a set of general guidelines for the structure of membranes of higher organisms: some of these rules may be wrong. But at this stage it seems useful to sharpen our thoughts in this way and thereby focus attention on various specific points. 1) The basis of a membrane is a lipid bilayer with (i) choline phospholipids and glycolipids in the external half and (ii) amino (and possibly some choline) phospholipids in the cytoplasmic half. There is effectively no lipid exchange across the bilayer (unless enzymatically catalyzed) (68). 2) Some proteins extend across the bilayer. Where this is so, they will in general have carbohydrate on their surface remote from the cytoplasm. This carbohydrate may prevent the protein diffusing out of the membrane into the cytoplasm; it acts as a lock on the protein. 3) Just as lipids do not flip-flop, proteins do not rotate across the membrane. Lateral motion or rotation of lipids and proteins in the plane of the bilayer may be expected. 4) Most membrane protein is associated with the inner, cytoplasmic, urface of the membrane. Proteins are not usually associated exclusively with the outer half of the lipid bilayer. 5) Membrane proteins are a special class of cytoplasmic proteins, not of secreted proteins. 相似文献
10.
铝胁迫下钙对小麦根系细胞质膜ATP酶活性和膜脂组成的效应 总被引：4，自引：0，他引：4
比较了在铝胁迫条件下钙对耐铝性不同的2个小麦品种Altas66、Scout66根细胞质膜ATP酶活性、膜脂和脂肪酸组成的影响。结果表明,铝胁迫下增加营养液中的钙浓度,可提高质膜H~+-ATP酶活性和磷脂含量,降低Ca~(2+)-ATP酶活性和糖脂含量;Altas66的亚麻酸含量下降,其它组分略有上升,不饱和指数和双键指数下降;Scout66的亚麻酸含量明显上升,棕榈酸则下降明显,其它组分也略有降低,不饱和指数和双键指数明显上升。 相似文献
11.
A G protein directly regulates mammalian cardiac calcium channels 总被引：45，自引：0，他引：45
A Yatani J Codina Y Imoto J P Reeves L Birnbaumer A M Brown 《Science (New York, N.Y.)》1987,238(4831):1288-1292
A possible direct effect of guanine nucleotide binding (G) proteins on calcium channels was examined in membrane patches excised from guinea pig cardiac myocytes and bovine cardiac sarcolemmal vesicles incorporated into planar lipid bilayers. The guanosine triphosphate analog, GTP gamma S, prolonged the survival of excised calcium channels independently of the presence of adenosine 3',5'-monophosphate (cAMP), adenosine triphosphate, cAMP-activated protein kinase, and the protein kinase C activator tetradecanoyl phorbol acetate. A specific G protein, activated Gs, or its alpha subunit, purified from the plasma membranes of human erythrocytes, prolonged the survival of excised channels and stimulated the activity of incorporated channels. Thus, in addition to regulating calcium channels indirectly through activation of cytoplasmic kinases, G proteins can regulate calcium channels directly. Since they also directly regulate a subset of potassium channels, G proteins are now known to directly gate two classes of membrane ion channels. 相似文献
12.
【背景】双孢蘑菇采后极易发生开伞、失水及褐变等品质劣变现象,极大地影响了其贮藏品质和商业价值。前期研究已证实纳米包装可有效延缓双孢蘑菇采后的品质劣变,但其保鲜机制仍不清晰。【目的】本研究通过串联质谱标记（TMT）定量蛋白质组学技术,对纳米包装和普通聚乙烯包装的双孢蘑菇贮藏期间的差异表达蛋白进行分析,进一步探究纳米包装保鲜双孢蘑菇的作用机制。【方法】以双孢蘑菇为研究对象,用纳米包装对其进行保鲜,并以普通聚乙烯包装作为对照。对贮藏期间双孢蘑菇进行蛋白提取和胰蛋白酶解,并通过TMT标记及液相色谱串联质谱检测,筛选出差异表达蛋白,结合生物信息学分析,研究差异蛋白所参与的主要代谢途径,同时利用实时荧光定量聚合酶链式反应（qPCR）技术,在基因层面验证差异蛋白的表达水平。【结果】纳米包装有效维持了双孢蘑菇的外观品质,并且延缓了细胞膜透性的增加。随着贮藏时间的增加,两组包装的差异蛋白数目增多,在贮藏中期（6 d）和贮藏末期（10 d）,差异蛋白分别达到62个和148个,其中纳米包装和普通包装有共同差异蛋白22个。结合生物信息学分析,发现这些差异蛋白主要与能量代谢和脂代谢等功能途径相关。对脂代谢途径进... 相似文献
13.
The objective of this study was to determine the direction of membrane lipid flow in locomoting cells. The plasma membrane of human polymorphonuclear leukocytes was stained with a fluorescent lipid analog dihexadecanoyl indocarbocyanine. A line was photobleached on the cell surface perpendicular to the direction of cell motion. Low-light-level fluorescence microscopy and digital image-processing techniques were used to analyze a series of images taken at short intervals after photobleaching. The bleached line remained visible for about 5 seconds before being erased by diffusional recovery. Examination of fluorescence intensity profiles allowed a comparison to be made between the velocities of line and cell movement. Results indicate that the bleached line moves forward with the same velocity as the cell during locomotion, refuting the retrograde lipid flow model of locomotion. Instead, the plasma membrane lipid appears to move forward according to either the unit movement of membrane or the tank track model of locomotion. 相似文献
14.
胆固醇是维持细胞膜脂筏稳定结构重要组分。一些囊膜病毒感染过程依赖胆固醇。研究利用Real Time PCR和病毒滴度试验,分析细胞膜和病毒囊膜胆固醇是否影响鸡传染性支气管炎病毒(IBV)感染鸡胚肾(CEK)细胞。结果表明,胆固醇萃取剂甲基-β-环糊精去除细胞膜胆固醇后,可抑制IBV感染CEK细胞并呈剂量依赖性,补充外源性胆固醇后,IBV感染力部分恢复,说明IBV感染依赖细胞膜胆固醇;去除细胞膜胆固醇可影响IBV感染侵入和释放过程。去除病毒囊膜胆固醇对IBV感染力无显著影响。IBV感染CEK细胞时依赖细胞膜胆固醇,而非病毒囊膜胆固醇。 相似文献
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17.
Glotzer M 《Science (New York, N.Y.)》2005,307(5716):1735-1739
After anaphase onset, animal cells build an actomyosin contractile ring that constricts the plasma membrane to generate two daughter cells connected by a cytoplasmic bridge. The bridge is ultimately severed to complete cytokinesis. Myriad techniques have been used to identify proteins that participate in cytokinesis in vertebrates, insects, and nematodes. A conserved core of about 20 proteins are individually involved with cytokinesis in most animal cells. These components are found in the contractile ring, on the central spindle, within the RhoA pathway, and on vesicles that expand the membrane and sever the bridge. Cytokinesis involves additional proteins, but they, or their requirement in cytokinesis, are not conserved among animal cells. 相似文献
18.
Ma D Zerangue N Lin YF Collins A Yu M Jan YN Jan LY 《Science (New York, N.Y.)》2001,291(5502):316-319
Little is known about the identity of endoplasmic reticulum (ER) export signals and how they are used to regulate the number of proteins on the cell surface. Here, we describe two ER export signals that profoundly altered the steady-state distribution of potassium channels and were required for channel localization to the plasma membrane. When transferred to other potassium channels or a G protein-coupled receptor, these ER export signals increased the number of functional proteins on the cell surface. Thus, ER export of membrane proteins is not necessarily limited by folding or assembly, but may be under the control of specific export signals. 相似文献
19.
Protein translocation across biological membranes 总被引：1，自引：0，他引：1
Subcellular compartments have unique protein compositions, yet protein synthesis only occurs in the cytosol and in mitochondria and chloroplasts. How do proteins get where they need to go? The first steps are targeting to an organelle and efficient translocation across its limiting membrane. Given that most transport systems are exquisitely substrate specific, how are diverse protein sequences recognized for translocation? Are they translocated as linear polypeptide chains or after folding? During translocation, how are diverse amino acyl side chains accommodated? What are the proteins and the lipid environment that catalyze transport and couple it to energy? How is translocation coordinated with protein synthesis and folding, and how are partially translocated transmembrane proteins released into the lipid bilayer? We review here the marked progress of the past 35 years and salient questions for future work. Subcellular compartments have unique protein compositions, yet protein synthesis only occurs in the cytosol and in mitochondria and chloroplasts. How do proteins get where they need to go? The first steps are targeting to an organelle and efficient translocation across its limiting membrane. Given that most transport systems are exquisitely substrate specific, how are diverse protein sequences recognized for translocation? Are they translocated as linear polypeptide chains or after folding? During translocation, how are diverse amino acyl side chains accommodated? What are the proteins and the lipid environment that catalyze transport and couple it to energy? How is translocation coordinated with protein synthesis and folding, and how are partially translocated transmembrane proteins released into the lipid bilayer? We review here the marked progress of the past 35 years and salient questions for future work. 相似文献
20.
Heo WD Inoue T Park WS Kim ML Park BO Wandless TJ Meyer T 《Science (New York, N.Y.)》2006,314(5804):1458-1461
Many signaling, cytoskeletal, and transport proteins have to be localized to the plasma membrane (PM) in order to carry out their function. We surveyed PM-targeting mechanisms by imaging the subcellular localization of 125 fluorescent protein-conjugated Ras, Rab, Arf, and Rho proteins. Out of 48 proteins that were PM-localized, 37 contained clusters of positively charged amino acids. To test whether these polybasic clusters bind negatively charged phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] lipids, we developed a chemical phosphatase activation method to deplete PM PI(4,5)P2. Unexpectedly, proteins with polybasic clusters dissociated from the PM only when both PI(4,5)P2 and phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] were depleted, arguing that both lipid second messengers jointly regulate PM targeting. 相似文献