Abstracts » Zoology and wildlife conservation

Isozyme-selective stimulation of phospholipase C-beta-2 by G protein beta-gamma-subunits

Article Abstract:

Many extracellular signalling molecules regulate target cell function through reactions involving phospholipase C (PLC). Often G proteins are involved in regulating PLC in these reactions. Two forms of PLC, PLC-beta-1 and PLC-beta-2, have been shown to be differentially stimulated by free G protein beta-gamma subunits. This stimulation is isozyme-selective with PLC-beta-2 being its prime target. Thus, PLC-beta-2 stimulation by beta-gamma subunits may play an important role in PLC stimulation by G proteins.

Cellular control mechanisms, Cell regulation

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Osmotic stress activates phosphatidylinositol-3,5-bisphosphate synthesis

Article Abstract:

Inositol phospholipids are important in cell signalling systems. It has been shown that Saccharomyces cerevisiae and Schizosaccharomyces pombe yeasts rapidly synthesize phosphatidy-linositol-3,5-bisphosphate when hyperosomotically stressed. This involves the activation of a PtdIns3P 5-OH kinase, and indicates that phosphatidy-linositol-3,5-bisphosphate may play a part in sorting vesicular proteins.

Observations, Eukaryotic cells, Cells (Biology), Eukaryotes, Phospholipids, Inositol

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Regulation by cAMP-dependent protein kinase of a G-protein-mediated phospholipase C

Article Abstract:

The cyclic AMP-dependent protein kinase (PKA) suppresses the activity of the phospholipase C (PLC)-beta-2 subunit which is activated by the G-beta-gamma protein in COS-7 cells. PKA has no effect on PLC isoforms that are activated by G-alpha. The suppression is due to the rapid phosphorylation of PLC-beta-2 serine amino acids. PKA and its isoforms have no suppressive effect on PLC isoforms.

Physiological aspects, Protein kinases, Enzyme inhibitors

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