KT5823 activates human neutrophils and fails to inhibit cGMP-dependent protein kinase phosphorylation of vimentin.

The effectiveness of the cGMP-dependent protein kinase inhibitor, KT5823, was investigated in human neutrophils. KT5823 did not inhibit the cGMP-dependent protein kinase mediated in vitro, or in situ phosphorylation of vimentin, a known substrate for this enzyme in activated neutrophils. In addition, KT5823 was shown to induce dramatic shape changes in neutrophils, suggesting it has an activating effect upon the cells.