Membrane fusion-inhibiting peptides do not inhibit influenza virus fusion or the Ca(2+)-induced fusion of negatively charged vesicles.

Stegmann, Toon

doi:10.1016/s0021-9258(19)74194-5

Cited by 5 publications

(2 citation statements)

References 37 publications

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“…Having established that annexin II can facilitate virus-anPL interactions, we next investigated whether AIItm can contribute to the fusion of CMV with anPL-containing membranes. To do so, the fluorescent amphiphile R18 was incorporated into the CMV envelope at the minimal amount that induces significant autoquenching (>70%), and probe dilution due to fusion with unlabeled vesicles was followed by fluorescence dequenching (30,(38)(39)(40). To avoid the possibility that the observed rates of fusion were dependent on the rate of binding, as previously described by Nir et al (41), we used right-angle light scattering at 320 nm (data not shown) to establish concentrations of CMV and PCPS that ensured particle association was instantaneous compared to the rate of R18-CMVvesicle fusion even at the lowest amount of AIItm (2 nM).…”

Section: Resultsmentioning

confidence: 99%

“…Having established that annexin II can bridge CMV to anPL membranes and fulfill the proposed virus receptor function, we next investigated the possibility that fusion of CMV to anPL-containing vesicles may also be facilitated by annexin II. To follow fusion, the well-documented (30,(38)(39)(40) amphipathic fluorescent probe R18 was incorporated into the CMV envelope. We observed that AIItm (18 nM) enhanced the apparent rate of fusion by at least 5-fold under the conditions employed and in accord with the anPL binding of annexin II was dependent on Ca 2+ .…”

Section: Discussionmentioning

confidence: 99%

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Annexin II Enhances Cytomegalovirus Binding and Fusion to Phospholipid Membranes

et al. 1999

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A number of studies have suggested that the anionic phospholipid (anPL)-binding protein annexin II may play a role in cytomegalovirus (CMV) infection. Since annexin II has been shown to mediate aggregation and fusion of certain membranes, we investigated whether these properties could be exploited by CMV directly. The experiments showed that purified annexin II, but not the homologous protein annexin V (AnV), can mediate the binding of 35S-CMV (strain AD169) to anPL-coated microtiter wells. This association required Ca2+, could be titrated by varying either annexin II (apparent Kd = 4 x 10(-)8 M) or 35S-CMV, was inhibited by unlabeled CMV, and was observed for the heterotetrameric or monomeric form of annexin II. In experiments utilizing the fluorescence dequenching of octadecyl rhodamine incorporated into the CMV envelope, annexin II was furthermore found to enhance the rate of virus-anPL vesicle fusion. The observed fusion was dependent on the concentration of annexin II, Ca2+, and anPL and was mediated principally by the heterotetramer. Interestingly, AnV was observed to inhibit the effects of annexin II on CMV fusion but not binding to anPL, which indicates that annexin II enhances these processes by distinct mechanisms. The results presented here provide the first direct evidence that annexin II has the capacity to bridge CMV to a phospholipid membrane and to enhance virus-membrane fusion. These observations furthermore suggest that AnV may regulate the fusogenic function of annexin II.

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