Latrotoxin‐like properties of a protein from brain

Zhukareva, Victoria; Shatursky, Oleg Ya.; Lishko, V. K.; Malysheva, M. K.; Terletskaya, Ya. T.; Tsygankova, Oxana M.; Ev, Grishin

doi:10.1016/0014-5793(92)80849-c

Cited by 7 publications

(4 citation statements)

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“…This complex is formed by mixing the aqueous content of two liposome populations, one of which contains terbium, while another contains dipicolinic acid [5][6][7]. With the use of this technique, we showed that L protein displayed a fusogenic effect in the negatively charged liposome systems, but in the case of liposomes composed of phosphatidylcholine L protein was inactive.…”

Section: Resultsmentioning

confidence: 94%

“…In particular, some similar properties of L protein and t Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine. 2 Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine.a-latrotoxin, which were studied in experiments with artificial phospholipid membranes, supported this supposition [5]. It turned out [6] that similarly to a-latrotoxin, L protein is spontaneously incorporated into the membrane and stimulates fusion of negatively charged liposomes.…”

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confidence: 84%

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Membranotropic properties of latrotoxin-like protein: Studies on liposomes

et al. 1998

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Fusion and changes in permeability ot' artificial pho~pholipid vesicles (liposomes) caused by the influence of a-latrotoxin-like protein (L protein) from the gray matter of the bovine brain were studied using a hydrophobic fluorescent probe, RI8. It was shown that L protein stimulates fusion of negatively charged lilx)somes. This effect becomes stronger In acidified media. The influence of L protein on the permeability of phtmphatidylcholine Ilpo~me membrane is also a pH-dependent process. INTRODUCTIONFusion of the membrane structures is one of the key steps in the process of neurosecretion. During recent years, many proteins and protein complexes involved in membrane fusion in the course of neurotransmitter release were identified [1 ]. However, the molecular mechanism of this phenomenon is still not clear.It is known [2 ] that a-latrotoxin, a natural toxin from Kara-kurt black widow spider venom, being joined to a high specific receptor on the cell membrane, causes massive efflux of a neurotransmitter from the cell. In vitro investigations [3] showed that a-latrotoxin is capable of causing fusion of synaptic vesicles with synaptosomal membranes.In the cytoplasm obtained from the cells of the bovine brain, a soluble protein (molecular mass 90 kdalton), possessing antigenic determinants similar to those of a-latrotoxin, was found earlier [4]. It was supposed that this isolated protein (henceforth called ct-latrotoxin-like protein, or L protein), is an intracellular agent involved in the process of neurosecretion, and a-latrotoxin can be considired its functional analog. In particular, some similar properties of L protein and t Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine. 2 Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine.a-latrotoxin, which were studied in experiments with artificial phospholipid membranes, supported this supposition [5]. It turned out [6] that similarly to a-latrotoxin, L protein is spontaneously incorporated into the membrane and stimulates fusion of negatively charged liposomes. In addition, the degree of liposome fusion in the presence of L protein considerably depends on pH of the media, and changes with protein molecule modifications [7 ]. The results of model experiments can provide us with substantial information about the properties and mechanisms of L protein effects.Our paper presents the results of studies of L protein interaction with artificial phospholipid vesicles (liposomes). With the use of this model system, we showed that L protein possesses pronounced membranotropic properties, which are displayed in the changes of liposome permeability and fusion in the presence of the protein. METHODSL protein was isolated from the cytoplasm obtained from the gray matter of the bovine brain. The tissue was homogenized in the solution containing (mM): sucrose, 250; EDTA, 0.5; tris-HCl, 20 (pH 7.4); phenytmethylsulfonyi fluoride, 0.1. The homogenate was centrifuged for 60 min at 100,000g. NaCl was added t...

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Section: Resultsmentioning

confidence: 94%

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confidence: 84%

Membranotropic properties of latrotoxin-like protein: Studies on liposomes

et al. 1998

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“…A cytoplasmic latrotoxin-like brain protein, or L protein (interacting with polyclonal antibodies against a-latrotoxin), was earlier isolated from the bovine brain cortex [5,6 ]. L protein was shown to promote fusion of negatively charged liposomes [7 ], and this effect significantly increased at a pH shift from 7.5 to 6.0.…”

Section: Resultsmentioning

confidence: 99%

Membrane fusion in model systems

et al. 1997

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“…The results of investigations of properties of this protein with the use of various model systems showed that the protein, similarly to latrotoxin, forms potential-dependent cation-selective channels in the lipid bilayer membranes [121 and induces fusion of artificial phospholipid vesicles (liposomes) [12,13]. Some similar characteristics of this protein (named latrotoxin-like, or L protein), and latrotoxin (the latter is know to cause massive release of a neurotransmitter from the ceils) let us speculate about L protein participation in the neurosecretory process in the cells.…”

Section: Introductionmentioning

confidence: 99%

Some characteristics of fusogenic activity of cytoplasmic latrotoxin-like brain protein

et al. 1998

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We studied fusion of negatively charged artificial phospholipid vesicles (liposomes) in the presence of two electrophoretic fractions (molecular mass of about 90 and 50 kdalton) of latrotuxin-Iike (L) protein. It was shown that both fractious are capable of causing liposome fusion in acidic media. Treatment o[ native preparations of L protein with NEM depr~d their fusogenic activity. Some common characteristics of L protein and well-known fusogenic proteins allow us to account for the possibility of participation of L protein in fusion of the membranes in the cell. INTRODUCTIONMany publications have appeared in the last few years devoted to the study of fusion of different membrane structures in live cells. Fusion of the membranes is one of the crucial steps both in the neurosecretory processes, when synaptic vesicles interact with the plasma membrane during neurotransmitter efflux and subsequent endocytosis [I], and in the processes occurring in the course of formation and functioning of the Golgi apparatus [2 ], or during the membrane protein biogenesis with the involvement of intraceUular membrane vesicles [3 ].It is known that synaptic vesicle fusion with the plasma membrane and fusion of intracellular membrane vesicles are governed by general principles, but display some specific characteristics. In both cases, membrane and some cytoplasmic proteins [4 ] are involved in the process of fusion providing approaching and fusion of the membrane structures. According to the most developed hypothesis concerning possible mechanisms of this process, an important moment in the sequence of events leading to fusion of the membrane structures is interaction of small proteins distributed on the cytoplas- Recently there has been discussion about participation of a cytosolic protein with the molecular mass of 97 kdalton (p97), or its complex with a protein with the molecular mass of 47 kdalton, in fusion of different types of membranes [2,9 ]. p97 seems to resemble very much the cytoplasmic protein sensitive to NEM. Both proteins can function as structurally homologous NEMsensitive soluble Mg-ATPases. There is strong evidence that both p97 and NEM-sensitive protein are involved in the processes of membrane fusion, but as regulators of fusion they have different sites of action. Participation of p97 in the process of reconstruction of the Golgi apparatus from its fragments is relatively well studied, but the role of this agent in the processes of neurosecretion remains quite obscure. The hypothesis mentioned above [5] is based on the experimental data about protein-protein interactions. At the same time, data were obtained about some lipids playing an important role in the process of fusion [10].Despite the existence of a rather fundamental hypothesis about fusion of the membrane structures in the process of cell vital activity, the molecular mechanism of this phenomenon still remains unclear. Because of this, model systems, in which one can rather easily modify protein and lipid composition of artificial membranes making it...

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Latrotoxin‐like properties of a protein from brain

Cited by 7 publications

References 8 publications

Membranotropic properties of latrotoxin-like protein: Studies on liposomes

Membranotropic properties of latrotoxin-like protein: Studies on liposomes

Membrane fusion in model systems

Some characteristics of fusogenic activity of cytoplasmic latrotoxin-like brain protein

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