New and noteworthy host records for some North American and Colombian spider wasps (Hymenoptera: Pompilidae)

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  New and noteworthy host records for some North American and Colombian spider wasps (Hymenoptera: Pompilidae) Abstract New and noteworthy parasitoid/host records for 47 North American and Colombian species and subspecies of spider wasps (Hymenoptera: Pompilidae) are listed in taxonomic order following the Catalog of Hymenoptera in America North of Mexico (Krombein 1979). Te records represent an extension of previous host studies by Kurczewski and various co-authors. New genus and/or species host records are given for the genera and subgenera  Calopompilus  Ashmead,  Pepsis  Fabricius,  Hemipepsis  Dahlbom,  Priocnessus  Banks,  Entypus  Dahlbom,  Cryptocheilus  Panzer,  Priocnemissus  Haupt,  Caliadurgus  Pate,  Dipogon  Fox,  Phanagenia  Banks,  Auplopus  Spinola,  Ageniella  Banks,  Aporus  Spinola,  Episyron  Schiødte,  Poecilopompilus...

Molecular mechanism of α-latrotoxin action

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Molecular mechanism of α-latrotoxin action

Abstract


The potent neurotoxic venom of the black widow spider contains a cocktail of seven phylum-specific latrotoxins (LTXs), but only one, α-LTX, targets vertebrates. This 130 kDa toxin binds to receptors at presynaptic nerve terminals and triggers a massive release of neurotransmitters. It is widely accepted that LTXs tetramerize and insert into the presynaptic membrane, thereby forming Ca2+-conductive pores, but the underlying mechanism remains poorly understood. LTXs are homologous and consist of an N-terminal region with three distinct domains, along with a C-terminal domain containing up to 22 consecutive ankyrin repeats. Here we report the first high resolution structures of the vertebrate-specific α-LTX tetramer in its prepore and pore state. Our structures, in combination with AlphaFold2-based structural modeling and molecular dynamics simulations, reveal dramatic conformational changes in the N-terminal region of the complex. Four distinct helical bundles synchronously rearrange to progressively form a highly stable 15 nm cation-impermeable coiled-coil stalk. This stalk, in turn, positions an N-terminal pair of helices within the membrane, thereby enabling the assembly of a cation-permeable channel. Taken together, these data unveil a unique mechanism for membrane insertion and channel formation, characteristic of the LTX family, and provide the necessary framework for advancing novel therapeutics and biotechnological applications.


Molecular mechanism of α-latrotoxin action Bjoern Udo Klink, Azadeh Alavizargar, Kalyankumar Karthik Subramaniam, Minghao Chen, Andreas Heuer, Christos Gatsogiannis
bioRxiv 2024.03.06.583760; doi: https://doi.org/10.1101/2024.03.06.583760