Resumen:
lc11a1 (formerly Nramp1) is a proton/divalent cation transporter
that regulates cation homeostasis in macrophages.
Slc11a2 mediates divalent cation uptake via the gut and delivery
into cells. The mode of action of the two transporters remains
controversial. Heterologous expression in frog oocytes shows
Slc11a2 is a symporter, whereas Slc11a1 is an antiporter fluxing
divalent cations against the proton gradient. This explains why
Slc11a2, but not Slc11a1, can complement EGTA sensitivity in
smf1 /smf2 /smf3 yeast. However, some studies of transport
in mammalian cells suggest Slc11a1 is a symporter. We now
demonstrate that Slc11a1, but not Slc11a2, complements a divalent
cation stress phenotype in bsd2 /rer1 yeast. This is the
first description of a yeast complementation assay for Slc11a1
function. Given the prior demonstration in frog oocytes that
Slc11a1 acts as an antiporter, the most plausible interpretation
of the data is that Slc11a1 is rescuing bsd2 /rer1 yeast b