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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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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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Dev Cell,
2002]
Presenilins mediate they-secretase cleavage of Notch transmembrane receptors as well as the transmembrane P-amyloid precursor protein (PAPP), but they are not thought to accomplish this alone. Recent genetic screens in C. elegans, presented in this issue of Developmental Cell, identify two genes that are essential to gamma-secretase activity and may interact with presenilins.
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J Cell Biol,
2007]
Cells must break symmetry to acquire polarity. Microtubules have been implicated in the induction of asymmetry in several cell types, but their role in the Caenorhabditis elegans zygote, a classic polarity model, has remained uncertain. One study (see Tsai and Ahringer on p. 397 of this issue) brings new light to this problem by demonstrating that severe loss of microtubules impairs polarity onset in C. elegans.
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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.