S. Tsuyama et al., Effects of mono-ADP-ribosylation on cytoskeletal actin in chromaffin cellsand their release of catecholamine, INT J BIO C, 31(5), 1999, pp. 601-611
Citations number
35
Categorie Soggetti
Biochemistry & Biophysics
Journal title
INTERNATIONAL JOURNAL OF BIOCHEMISTRY & CELL BIOLOGY
To better understand the physiological role of mono-ADP-ribosylation in ani
mals, we examined its role in chromaffin cells, Monoclonal antibodies again
st rat brain ADP-ribosylhydrolase were prepared, one of which (9E7) complet
ely inhibited the enzyme's activity with ADP-ribosylated actin as the subst
rate. After actin monomers were polymerized by the addition of Mg2+, mono-A
DP-ribosylation induced actin depolymerization. After mono-ADP-ribosylation
, the actin monomers did not polymerize by the addition of Mg2+. Polymerize
d actin cosedimented with chromaffin granules but mono-ADP-ribosylated acti
n did not. After ADP-ribosylhydrolase on the membrane of chromaffin granule
s was incubated with 9E7, mono-ADP-ribosylated actin did not cosediment wit
h chromaffin granules. when chromaffin cells permeabilized with saponin wer
e incubated with NAD and 9E7, actin and rho protein was mono-ADP-ribosylate
d and stimulated catecholamine release from the cells. In histochemical exp
eriments, catecholamine and actin filaments disappeared when the permeabili
zed chromaffin cells were treated with NAD and 9E7. These findings indicate
that mono-ADP-ribosylation breaks the actin barrier in order to move granu
les during exocytosis, and ADP-ribosylactin hydrolase may keep the granules
within the actin barrier. (C) 1999 Elsevier Science Ltd. All rights reserv
ed.