The interaction of N-formyl peptide chemoattractant receptors with
the membrane skeleton is energy-dependent
Cell Signal, 6 (8):
943-7 (November 1994)Klotz, K N Jesaitis, A J R01 AI 22735/AI/NIAID NIH HHS/United States
Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.
England Cellular signalling Cell Signal. 1994 Nov;6(8):943-7..Abstract
Desensitization of N-formyl peptide chemoattractant receptors (FPR)
in human neutrophils is thought to be achieved by lateral segregation
of receptors and G proteins within the plane of the plasma membrane
resulting in an interruption of the signalling cascade. Direct coupling
of FPR to membrane skeletal actin appears to be the basis of this
process; however, the molecular mechanism is unknown. In this study
we investigated the effect of energy depletion on formation of FPR-membrane
skeleton complexes. In addition the effect of the protein kinase
C inhibitor stauroporine and the phosphatase inhibitor okadaic acid
on coupling of FPR to the membrane skeleton was studied. Human neutrophils
were desensitized using the photoreactive agonist N-formyl-met-leu-phe-lys-N'-125I2(p-azidosalicylamido)ethyl-1,3'
- dithiopropionate (fMLFK-125IASD) after ATP depletion with NaF
or after incubation with the respective inhibitors. The interaction
of FPR with the membrane skeleton was studied by sedimentation of
the membrane skeleton-associated receptors in sucrose density gradients.
Energy depletion of the cells markedly inhibited the formation of
FPR-membrane skeleton complexes. This does not appear to be related
to inhibition of protein phosphorylation due to ATP depletion because
inhibition of protein kinases and phosphatases had no significant
effect on coupling of FPR to the membrane skeleton. We conclude,
therefore, that coupling of FPR to the membrane skeleton is an energy-dependent
process which does not appear to require modification of the receptor
protein by phosphorylation.