PHENYLARSINE OXIDE MODULATES INTRACELLULAR DYNAMICS OF ALKALINE PHOSPHATASE-CONTAINING GRANULES IN HUMAN NEUTROPHILS STIMULATED WITH PHORHOL MYRISTATE ACETATE OR IGG-COATED LATEX BEADS
T. Kobayashi et al., PHENYLARSINE OXIDE MODULATES INTRACELLULAR DYNAMICS OF ALKALINE PHOSPHATASE-CONTAINING GRANULES IN HUMAN NEUTROPHILS STIMULATED WITH PHORHOL MYRISTATE ACETATE OR IGG-COATED LATEX BEADS, Acta histochemica et cytochemica, 30(5-6), 1997, pp. 537-544
We studied the intracellular dynamics of alkaline phosphatase (ALPase)
-containing granules in human neutrophils exposed to a phosphotyrosine
phosphatase inhibitor, phenylarsine oxide (PAO). Unstimulated neutrop
hils showed ALPase activity in short rod-shaped intracellular compartm
ents distributed dispersedly throughout the cytoplasm. Enzyme activity
was observed in elongated tubular structures and vacuoles in cells st
imulated with a protein kinase C activator, phorbol myristate acetate
(PMA). When cells were exposed to PAO followed by stimulation with PMA
, the enzyme activity was visualized in intracellular compartments, lo
calized in the pericytoplasm, which were associated with the plasma me
mbrane. A tyrosine kinase inhibitor, erbstatin, prevented this re-loca
tion of ALPase-containing granules. PAO also prevented the association
of ALPase-containing granules with the limiting membrane of phagosome
s containing IgG-coated latex beads. Biochemical studies demonstrated
that the upregulation of ALPase activity was not affected by exposure
to PAO in cells stimulated with PMA, but was inhibited by erbstatin in
cells exposed to PAO followed by stimulation with PMA. The present fi
ndings indicate that both tyrosine phosphorylation and phosphotyrosine
dephosphorylation are involved in the intracellular dynamics of ALPas
e-containing granules. and demonstrate that the dynamical alterations
of these granules are affected by different stimuli such as PMA or IgG
-coated latex beads.