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Science,
1995]
When it comes to G proteins, cell biologists have amassed a great wealth of material. They have identified nearly 30 of these proteins, which serve as key relays in the pathways that transmit signals from hormones, neurotransmitters, and other cellular regulators from the cell membrane to the interior. And studies with cultured cells have enabled researchers to learn a great deal about the biochemistry of G proteins...
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J Cell Biol,
2020]
The mechanisms that control how the two parental pronuclei fuse in the first mitosis of the embryo are poorly understood. In this issue, Rahman et al. (2020. J. Cell Biol.https://doi.org/10.1083/jcb.201909137) found that membrane fusion between pronuclear envelopes, followed by fenestration, promotes pronuclear fusion.
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J Cell Biol,
2019]
In this issue, Zhang et al. (2019. <i>J. Cell. Biol.</i> https://doi.org/10.1083/jcb.201907196) describe a molecular mechanism by which cuticular damage in the nematode <i>C. elegans</i> leads to systemic induction of autophagy by signals propagated from sensory neurons via the TGF- signaling pathway.
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J Cell Biol,
2022]
During cytokinesis, microtubules become compacted into a dense midbody prior to abscission. Using genetic perturbations and imaging of C. elegans zygotes, Hirsch et al. (2022. J. Cell Biol.https://doi.org/10.1083/jcb.202011085) uncover an unexpected source of microtubules that can populate the midbody when central spindle microtubules are missing.
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[
Nature,
1992]
Supporters of large DNA sequencing projects will take heart (and find much to learn) from the report by J. Sulston and colleagues that appears on page 37 of this issue. Sulston et al. describe the first results of the Caenorhabditis elegans genome sequencing project, and have come up with not only hitherto unknown genes but also with fresh and biologically relevant information.
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Nat Neurosci,
2003]
In C. elegans, social and solitary feeding behavior can be determined by a single amino acid change in a G protein-coupled receptor. A new study identifies ligands for this receptor and suggests how changes in behavior evolve at the molecular level.
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[
Curr Biol,
2007]
Cytokinesis is regulated by both astral microtubules and the midzone microtubules of the mitotic apparatus. A new study in Caenorhabditis elegans has identified the polarity factor LET-99 and its heterotrimeric G-protein regulators as components of the signaling pathway downstream of astral microtubules.
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Worm,
2016]
Although several signaling pathways in oriented cell division have been well characterized such as delta/notch inductions or wnt/frizzled-based anterior-posterior polarity, there is strong evidence for additional signal pathways controlling early anterior-posterior polarity decisions. The homolog of the adhesion G protein-coupled receptor latrophilin, LAT-1 has been identified as a receptor essential for oriented cell division in an anterior-posterior direction of specific blastomeres in the early C. elegans embryo. We recently conducted a study aiming at clarifying the signals involved in LAT-1 function. We identified a Gs protein/adenylyl cyclase/cAMP pathway in vitro and demonstrated its physiological relevance in oriented cell division. By interaction with a Gs protein LAT-1 elevates cAMP levels. These data indicate that G-protein signaling in oriented cell division is not solely GPCR-independent. This commentary will discuss our findings in the context of the current knowledge of mechanisms controlling oriented cell division and anterior-posterior polarity. Further, we identify open questions which need to be addressed in the future.
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Nature,
2001]
The degredation of DNA is one of the hallmarks of programmed cell death (apoptosis). When forced to commit suicide, apoptotic cells - like good secret agents - grimly destroy their "instruction book," chewing up their genomic DNA into tiny morsels. Until now, only two DNA-destroying enzymes (nucleases) with a clear role in cell death were known, one in mammals and one in the nematode worm Caenorhabditis elegans. But, on pages 90-99 of this issue, Li and colleagues and Parrish and co-workers show that another nuclease, endonuclease G (endoG), also contributes to the carnage, and might even influence the likelihood that a cell will live or die.
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J Neurophysiol,
2007]
The work of Clark et al. in this issue of J. Neurophysiology extends the analysis of thermotaxis in C. elegans by providing a detailed analysis of the adaptation of thermotactic behavior. Previous work indicates that thermotaxis in C. elegans involves a biased random walk in which changes in temperature alter the duration of the runs that an animal makes between turns. Interestingly, the authors find that although behavioral responses to increases and decreases in temperature have opposite effects on run length, the two responses are of similar magnitude and adapt with similar kinetics. These properties are predicted to allow the system act as a band-pass filter that would be less sensitive to temperature fluctuations occurring on a time-scale significantly faster or slower than the time needed for an average run. This analysis of C. elegans thermotaxis raises potential parallels to bacterial chemotaxis, with the kinetics of adaptation playing an important role in determining the ability of the organism to sense a stimulus gradient. This raises the possibility that diverse organisms may exploit similar system properties to solve similar problems, such as the problem of responding robustly to subtle gradations in an external stimulus.