S. Chaudhuri et al., Serum deprivation leads to growth inhibition and protein tyrosine phosphorylation in Entamoeba histolytica, CURRENT SCI, 78(3), 2000, pp. 336-338
Growth of Entamoeba histolytica in culture was found to be entirely depende
nt upon the presence of serum in the culture media. Very little protein pho
sphorylation was detected in growing E. histolytica cells by quantitative i
mmunofluorescence and immunoblotting. Intense augumentation of antiphosphot
yrosine immunofluorescence was observed after 1 h of serum deprivation. Ant
iphosphotyrosine immunofluorescence levels increased moderately between 1 h
and 1.5 h of serum deprivation, after which no further increase was observ
ed till 4 h serum deprivation. At 1 h of serum deprivation, a very high tyr
osine kinase activity was detected. Sodium orthovanadate, a potent tyrosine
phosphatase inhibitor, increased tyrosine phosphorylation of a 38 kDa prot
ein after 1 h of incubation and also inhibited the growth of E. histolytica
in culture. Our data demonstrated that protein tyrosine phosphorylation wa
s associated with growth inhibition of E. histolytica.