Localization of filipin-sterol complexes in cell membranes of eosinophils

Pimenta, Paulo; Souza, Wanderley de

doi:10.1007/bf02400973

Cited by 2 publications

(3 citation statements)

References 24 publications

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“…We confirmed previous reports that HPV16 internalization into HaCaT cells is clathrin dependent and does not involve caveola-mediated entry (62). Specifically, we used the caveolar entry inhibitor filipin, which binds to cholesterol in the plasma membrane (10,41,49,66). Filipin inhibits the initial entry of caveolae but does not seem to affect the downstream vesicles of the caveolar pathway.…”

Section: Discussionsupporting

confidence: 81%

Human Papillomavirus Type 16 Infection of Human Keratinocytes Requires Clathrin and Caveolin-1 and Is Brefeldin A Sensitive

Laniosz¹,

Dabydeen²,

Havens³

et al. 2009

J Virol

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Human papillomavirus type 16 (HPV16) has been identified as being the most common etiological agent leading to cervical cancer. Despite having a clear understanding of the role of HPV16 in oncogenesis, details of how HPV16 traffics during infection are poorly understood. HPV16 has been determined to enter via clathrin-mediated endocytosis, but the subsequent steps of HPV16 infection remain unclear. There is emerging evidence that several viruses take advantage of cross talk between routes of endocytosis. Specifically, JCV and bovine papillomavirus type 1 have been shown to enter cells by clathrin-dependent endocytosis and then require caveolin-1-mediated trafficking for infection. In this paper, we show that HPV16 is dependent on caveolin-1 after clathrin-mediated endocytosis. We provide evidence for the first time that HPV16 infection is dependent on trafficking to the endoplasmic reticulum (ER). This novel trafficking may explain the requirement for the caveolar pathway in HPV16 infection because clathrin-mediated endocytosis typically does not lead to the ER. Our data indicate that the infectious route for HPV16 following clathrin-mediated entry is caveolin-1 and COPI dependent. An understanding of the steps involved in HPV16 sorting and trafficking opens up the possibility of developing novel approaches to interfere with HPV16 infection and reduce the burden of papillomavirus diseases including cervical cancer.

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Section: Discussionsupporting

confidence: 81%

Human Papillomavirus Type 16 Infection of Human Keratinocytes Requires Clathrin and Caveolin-1 and Is Brefeldin A Sensitive

Laniosz¹,

Dabydeen²,

Havens³

et al. 2009

J Virol

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“…Thus, thin sections were used to visualize the filipin labelling, since membrane deformations produced by the filipin-sterol complexes were detectable in thin sections of the filipin-treated cells (7,25,27). In the unreacted abalone sperm, filipin-induced deformation was seldom observed on the inner acrosomal membrane, which was densely packed with IMPs (29).…”

Section: Discussionmentioning

confidence: 99%

“…Filipin has been shown to interact specifically with membrane cholesterols and the related 3-hydroxysterols (2, 3, 4, 22), producing unique hemispherical lesions which can be recognized in freeze-fracture replicas and in thin sections (5,7,18,25,27,37,39). A preliminary report of this work has been presented (35 Observations of thin sections of sperm treated with filipin provided additional information on ultrastructural changes of the membrane induced by filipin.…”

mentioning

confidence: 97%

Distribution of filipin-sterol complexes in Japanese abalone sperm during the acrosome reaction.

Shiroya

Sakai

1988

Cell Struct. Funct.

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ABSTRACT. The distribution of membrane sterols in the acrosome reaction of Japanese abalone sperm was studied by freeze-fracture techniques using a polyene antibiotic, filipin, as a probe for membrane sterols. In the unreacted sperm, the plasma membrane covering the acrosome showed a random distribution of filipin-sterol complexes, while in the outer acrosomal membrane, filipinsterol complexes were rarely observed. In the initial stage of the acrosome reaction, filipin-sterol complexes were found densely distributed in the plasma membrane throughout the acrosomal region. On the subjacent outer acrosomal membrane, filipin-sterol complexes were densely packed in the apical area, corresponding to the truncated cone region. This apical area consistently showed such regionalization of filipin-sterol complexes during the acrosome reaction. As the acrosomal process elongated, the intramembrane particle (IMP)-free areas which appeared in the acrosomal process membrane were found to be displaced by densely distributed filipin-sterol complexes. These results indicate a possible regionalization of membrane sterols related to the acrosome reaction.In marine invertebrates the acrosome reaction consists fundamentally of two requisites; exocytosis of the acrosomal vesicle to release lytic substances for dissolving the egg coats, and exposure of the newly formed acrosomal process to generate a site for fusion with the egg. Of particular interest is that membrane transformations occurring during the acrosome reaction involve the fusion between the plasma membrane and the outer acrosomal membrane at the apex of the acrosome, resulting in exocytosis, and rapid extension of the inner acrosomal membrane to form the acrosomal process membrane which may eventually fuse with the egg plasma membrane.A few freeze-fracture studies of abalone (29) and mammalian sperm (9,10,15,40) have demonstrated the regionalization of intramembrane particles (IMPs) associated with the acrosome reaction, while little information is available concerning the distribution of sterols in the sperm membrane during the acrosome reaction (12). Sterol is an important component of the cell membrane and plays a fundamental role in modulating the permeability and fluidity of membranes (6,24,33). Thus, the study of the distribution of sterol in the membranes is important in order to further understand the structural properties and functions of the membrane in relation to the acrosome reaction.In the present study, attempts have been made to investigate the distribution of sterols (usually cholesterol) in the membranes of abalone sperm during the 73

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Localization of filipin-sterol complexes in cell membranes of eosinophils

Cited by 2 publications

References 24 publications

Human Papillomavirus Type 16 Infection of Human Keratinocytes Requires Clathrin and Caveolin-1 and Is Brefeldin A Sensitive

Human Papillomavirus Type 16 Infection of Human Keratinocytes Requires Clathrin and Caveolin-1 and Is Brefeldin A Sensitive

Distribution of filipin-sterol complexes in Japanese abalone sperm during the acrosome reaction.

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