English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Activation of phospholipase D (PLD) in phagocytic leucocytes requires protein components present in both the plasma membrane and the cytosol, but the catalytic and regulatory factors are not fully defined. We have characterized the effect of guanosine 5'-[gamma-thio]triphosphate (GTP[S]) on the subcellular requirements for reconstitution of PLD activity, using a cell-free system from U937 human promonocytic leucocytes. Incubation of permeabilized cells with 100 microM GTP[S] resulted in a membrane-localized PLD activity which was independent of added cytosol. The PLD activity of membranes from GTP[S]-treated cells was 7-fold greater than the basal activity of control membranes, and could be further augmented by the addition of ATP. This was the first demonstration of a stable agonist-regulated PLD activity in membranes from phagocytic leucocytes which was quantitatively comparable with that seen in a fully reconstituted system. Cytosol from GTP[S]-treated cells had a decreased capacity to support PLD activation, consistent with GTP[S]-induced depletion of a factor essential for reconstitution of PLD activity. Incubation of isolated membrane and cytosol with GTP[S] also resulted in a cytosol-independent PLD activity in the re-isolated membranes. The effect of GTP[S] could be mimicked by guanosine 5'-[beta gamma-imido]triphosphate, but not by aluminium fluoride, consistent with the involvement of a low-molecular-mass GTP-binding protein(s). Incubation of isolated subcellular fractions with GTP[S], followed by removal of unbound nucleotide, suggested that at least one of the GTP-binding proteins involved in the membrane localization of PLD activity was itself present in the membrane fraction. These data were consistent with a model in which activation of GTP-binding protein(s) resulted in the stable assembly of an active PLD signalling complex at the membrane surface.

biochemical journal

Guanosine 5′-[γ-thio]triphosphate induces membrane localization of cytosol-independent phospholipase D activity in a cell-free system from U937 promonocytic leucocytes