Sf. Penc et al., A ROLE FOR A 70-KDA AMINO-TERMINAL FIBRONECTIN FRAGMENT IN SUPPORTINGSOLUBLE GELATIN INTERACTIONS WITH RAT PERITONEAL-MACROPHAGES, Journal of leukocyte biology, 58(5), 1995, pp. 501-509
Seventy-kilodalton amino-terminal and 180-kDa cell-binding fibronectin
fragments were used to determine which fibronectin domains support so
luble gelatin interactions with macrophages. At each time measured, in
tact and 180-kDa fibronectin supported significantly larger quantities
of cell-associated gelatin than control levels (P < 0.05), Throughout
the time course fibronectin supported more binding than 180 kDa, Seve
nty kilodalton did not augment gelatin binding until 2 h, but by 6 h 7
0 kDa supported more binding than intact fibronectin (P < 0.01), This
appeared to result from a cellular response initiated by 70-kDa-gelati
n interactions with the macrophages. Within 4 h the majority of gelati
n associated with cells under control conditions, and in the presence
of fibronectin or 180 kDa, was internalized, Seventy-kilodalton-mediat
ed binding remained localized primarily to the cell surfaces at all ti
mes, The macrophages partially degraded the internalized and external
gelatin fractions, These results demonstrate that intact fibronectin a
nd specific fibronectin fragments support soluble gelatin interactions
with macrophages.