Fragments from α-Actinin Insert into Reconstituted Lipid Bilayers

Wh, Goldmann; Jm, Teodoridis; Sharma, Chandra P.; Jl, Alonso Calderón; Isenberg, G.

doi:10.1006/bbrc.1999.1495

Cited by 11 publications

(6 citation statements)

References 34 publications

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“…This argument is supported by the fact that PG can interact with the positively charged polymers, proteins and divalent cations via electrostatic forces. 32,[42][43][44][45][46][47] On the other hand, at temperatures higher than the T m of lipids, rat plasma only slightly enhanced the temperature-dependent content release from liposomes regardless of the lipid composition (Fig. 4).…”

Section: Discussionmentioning

confidence: 99%

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Alteration in the Temperature-Dependent Content Release Property of Thermosensitive Liposomes in Plasma

Hosokawa

Sami

Kato

et al. 2003

CHEMICAL & PHARMACEUTICAL BULLETIN

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Liposomes have been proposed as carriers for the delivery of molecules to cells. They have been shown to enhance the efficacy of encapsulated drugs, prolonging the circulation time and reducing side effects. Moreover, the targeting of liposomes to desirable sites has been attempted. 1,2) In addition, a number of attempts have been made to develop functional liposomes, which can regulate the release of drugs responding to various stimuli, such as pH, [3][4][5][6] light 7,8) and temperature. 9-15)The liposomes injected into blood would be opsonized by serum components, and rapidly taken up by the reticuloendothelial system (RES) including the liver and spleen. [16][17][18][19][20] This is a major problem for researchers, because it is a significant disadvantage for the delivery of drugs to non-RES tissues. Moreover, some serum components have a destabilizing effect upon lipid vesicles and thereby cause leakage of liposomal contents. For example, high-density lipoprotein (HDL) is known to cause the disintegration of liposomes. 21,22) Yatvin et al. and Weinstein et al. reported an unique approach to controlling the release of drugs using temperaturesensitive liposomes in conjunction with local hyperthermia.9-11) The barrier efficiency of the membrane abruptly decreases near the gel-to-liquid crystalline phase transition temperature (T m ) of the phospholipid membrane. The temperature-sensitive liposomes have been designed to release a drug in response to local hyperthermia, during which a tumor was heated at temperatures of 41 to 45°C. Other strategies have been used for the production of temperature-sensitive liposomes. One example is the use of polymers, which are attached to the liposome to exhibit temperature-sensitivity and cause release of the internal content above a certain temperature. 14,15) In the development of the liposome, pharmaceutical scientists have been confronted with two difficulties. The first is how to prolong circulation time. Recently, the liposome surface has been modified with GM1 ganglioside 23) and polyoxyethylene derivatives, 24,25) which have some ability to escape the RES. The second is the problem regarding the stability of liposomes in systemic circulation after injection. In general, it is favorable for a drug delivery system (DDS) to have liposomes that are stable in the blood circulation, especially for chemotherapy and gene therapy. In addition, when trying to develop stimulus-sensitive liposomes, one should consider the influence of the serum components on the function of liposomes. Liu and Huang have observed that DOPEbased pH-sensitive liposomes lost their pH-sensitivity in the presence of serum. 26)Anionic lipids are frequently used in preparing liposomes for drug delivery. In the fluid state, negatively charged liposomes composed of phosphatidylglycerol (PG) interacted with serum components and caused an increase in the leakage of the encapsulated drug. 27) Therefore, it is necessary to investigate the effects of serum components on the temperature-dependent release propert...

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Section: Discussionmentioning

confidence: 99%

“…32) Figure 5 shows scanning calorimetric curves of the DPPC and the DPPC/DPPG liposomes. Without rat plasma, both of the liposomes exhibited a sharp thermal transition with a midpoint at 41°C and a pronounced pretransition at about 33°C.…”

Section: (mentioning

confidence: 99%

Alteration in the Temperature-Dependent Content Release Property of Thermosensitive Liposomes in Plasma

Hosokawa

Sami

Kato

et al. 2003

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…Although α-actinin is primarily found within cells, a number of reports have suggested its potential surface location or membrane insertion ( Dubernard et al ., 1997 ; Goldmann et al ., 1999 ; Deocharan et al ., 2002 ). To assess at which site Opc and α-actinin may interact (cell surface/intracellularly), initial studies used confocal microscopy to examine if any α-actinin was surface located.…”

Section: Resultsmentioning

confidence: 99%

“…This may result in degradation of the vacuole and the escape of bacteria into the cytoplasm where they may interact directly with cytosolic/cytoskeletal proteins. Alternatively, it is possible that proteins such as α-actinin that can insert into phospholipid bilayers ( Niggli and Gimona, 1993 ; Goldmann et al ., 1999 ) may be inserted into the phagocytic vacuolar membrane in a manner that allows bacterial interaction.…”

Section: Discussionmentioning

confidence: 99%

Neisseria meningitidisOpc invasin binds to the cytoskeletal protein α-actinin

Cunha¹,

Griffiths²,

Murillo³

et al. 2009

Cellular Microbiology

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SummaryNeisseria meningitidis Opc protein is an effective invasin for human endothelial cells. We have investigated novel human endothelial receptors targeted by Opc and observed that Opc-expressing bacteria interacted with a 100 kDa protein in wholecell lysates of human endothelial and epithelial cells. The identity of the protein was established as a-actinin by mass spectrometry. Opc expression was essential for the recognition of a-actinin whether provided in a purified form or in cell extracts. The interaction of the two proteins did not involve intermediate molecules. As there was no demonstrable expression of a-actinin on the surfaces of any of the eight cell lines studied, the likelihood of the interactions after meningococcal internalization was examined. Confocal imaging demonstrated considerable colocalization of N. meningitidis with a-actinin especially after a prolonged period of internalization. This may imply that bacteria and a-actinin initially occur in separate compartments and co-compartmentalization occurs progressively over the 8 h infection period used. In conclusion, these studies have identified a novel and an intracellular target for the N. meningitidis Opc invasin. Since a-actinin is a modulator of a variety of signalling pathways and of cytoskeletal functions, its targeting by Opc may enable bacteria to survive/translocate across endothelial barriers.

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“…Bindungsstellen für Actin und Phospholipide sind jeweils benachbart in dem aminoterminalen Kopfende lokalisiert. Der Nachweis für die Beteiligung der vermuteten Sequenzen an der Membranbindung wurde in diesem Fall nicht mit Hilfe von Peptiden, sondern durch die Anwendung von GST-Fusionsproteinen (siehe oben) erbracht, die nur dann erfolgreich in Modellmembranen eingebaut werden können, wenn die Lipid-bindenden Sequenzabschnitte zusammen mit dem Protein Glutathion-S-Transferase (GST) exprimiert werden [2].…”

Section: Abb 9 Ein Modell Wie Talin An Der Lipidgrenzfläche Organiunclassified

Cytoskelett und Zellmembran

Isenberg

2000

Biologie in unserer Zeit

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An der Grenzfläche zwischen Zellmembran und Cytoplasma entstehen in der Zelle permanent neue Interaktionsmöglichkeiten. Molekulare Anker, Brücken und Eiweißkaskaden sorgen für einen bidirektionalen Austausch von Information zwischen Zellinnerem und ‐äußerem. Zu wenig Beachtung finden bisher die Membranlipide. Sie sind jedoch von entscheidender Bedeutung für die Membranarchitektur und für die Regulation der Funktion assoziierter Cytoskelettproteine.

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Fragments from α-Actinin Insert into Reconstituted Lipid Bilayers

Cited by 11 publications

References 34 publications

Alteration in the Temperature-Dependent Content Release Property of Thermosensitive Liposomes in Plasma

Alteration in the Temperature-Dependent Content Release Property of Thermosensitive Liposomes in Plasma

Neisseria meningitidisOpc invasin binds to the cytoskeletal protein α-actinin

Cytoskelett und Zellmembran

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