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Find video protocols related to scientific articles indexed in Pubmed.
Cytotoxic cells kill intracellular bacteria through granulysin-mediated delivery of granzymes.
Cell
PUBLISHED: 02-24-2014
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When killer lymphocytes recognize infected cells, perforin delivers cytotoxic proteases (granzymes) into the target cell to trigger apoptosis. What happens to intracellular bacteria during this process is unclear. Human, but not rodent, cytotoxic granules also contain granulysin, an antimicrobial peptide. Here, we show that granulysin delivers granzymes into bacteria to kill diverse bacterial strains. In Escherichia coli, granzymes cleave electron transport chain complex I and oxidative stress defense proteins, generating reactive oxygen species (ROS) that rapidly kill bacteria. ROS scavengers and bacterial antioxidant protein overexpression inhibit bacterial death. Bacteria overexpressing a GzmB-uncleavable mutant of the complex I subunit nuoF or strains that lack complex I still die, but more slowly, suggesting that granzymes disrupt multiple vital bacterial pathways. Mice expressing transgenic granulysin are better able to clear Listeria monocytogenes. Thus killer cells play an unexpected role in bacterial defense.
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Mad2 prolongs DNA damage checkpoint arrest caused by a double-strand break via a centromere-dependent mechanism.
Curr. Biol.
PUBLISHED: 01-21-2010
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Eukaryotic cells employ a suite of replication and mitotic checkpoints to ensure the accurate transmission of their DNA. In budding yeast, both the DNA damage checkpoint and the spindle assembly checkpoint (SAC) block cells prior to anaphase. The presence of a single unrepaired double-strand break (DSB) activates ATR and ATM protein kinase homologs Mec1 and Tel1, which then activate downstream effectors to trigger G2/M arrest and also phosphorylate histone H2A (creating gamma-H2AX) in chromatin surrounding the DSB. The SAC monitors proper attachment of spindle microtubules to the kinetochore formed at each centromere and the biorientation of sister centromeres toward opposite spindle pole bodies. Although these two checkpoints sense quite different perturbations, recent evidence has demonstrated both synergistic interactions and cross-talk between them. Here we report that Mad2 and other SAC proteins play an unexpected role in prolonging G2/M arrest after induction of a single DSB. This function of the SAC depends not only on Mec1 and other components of the DNA damage checkpoint but also on the presence of the centromere located > or = 90 kb from the DNA damage. DNA damage induces epigenetic changes at the centromere, including the gamma-H2AX modification, that appear to alter kinetochore function, thus triggering the canonical SAC. Thus, a single DSB triggers a response by both checkpoints to prevent the segregation of a damaged chromosome.
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Identification of regulators of the innate immune response to cytosolic DNA and retroviral infection by an integrative approach.
Nat. Immunol.
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The innate immune system senses viral DNA that enters mammalian cells, or in aberrant situations self-DNA, and triggers type I interferon production. Here we present an integrative approach that combines quantitative proteomics, genomics and small molecule perturbations to identify genes involved in this pathway. We silenced 809 candidate genes, measured the response to dsDNA and connected resulting hits with the known signaling network. We identified ABCF1 as a critical protein that associates with dsDNA and the DNA-sensing components HMGB2 and IFI204. We also found that CDC37 regulates the stability of the signaling molecule TBK1 and that chemical inhibition of the CDC37-HSP90 interaction and several other pathway regulators potently modulates the innate immune response to DNA and retroviral infection.
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DNA damage checkpoint triggers autophagy to regulate the initiation of anaphase.
Proc. Natl. Acad. Sci. U.S.A.
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Budding yeast cells suffering a single unrepaired double-strand break (DSB) trigger the Mec1 (ATR)-dependent DNA damage response that causes them to arrest before anaphase for 12-15 h. Here we find that hyperactivation of the cytoplasm-to-vacuole (CVT) autophagy pathway causes the permanent G2/M arrest of cells with a single DSB that is reflected in the nuclear exclusion of both Esp1 and Pds1. Transient relocalization of Pds1 is also seen in wild-type cells lacking vacuolar protease activity after induction of a DSB. Arrest persists even as the DNA damage-dependent phosphorylation of Rad53 diminishes. Permanent arrest can be overcome by blocking autophagy, by deleting the vacuolar protease Prb1, or by driving Esp1 into the nucleus with a SV40 nuclear localization signal. Autophagy in response to DNA damage can be induced in three different ways: by deleting the Golgi-associated retrograde protein complex (GARP), by adding rapamycin, or by overexpression of a dominant ATG13-8SA mutation.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.