Down-regulation of chimeric mutant T200V
type I receptors. Cell surface binding in response to 10 ng/ml GM-CSF
was performed as described in MATERIALS AND METHODS. Each point
represents the mean (± SE) for all clones of the series assayed in
duplicate from two independent experiments. (A) AKR-2B fibroblast
clones T200V-10 and -12 (○) are compared with A105 wild-type control
(●). (B) Mv1Lu epithelial clones T200V-2 and -7 (□) are compared
with the mean of MB-9 and -18 as wild-type control (▪). (C) Mean
percentage of down-regulation of two different epithelial (▪, □)
and three fibroblast (●, ○) cell lines. Stable clones expressing
the T200V mutation (open symbols) in Mv1Lu (clones 2 and 7) and MDCK
(clones 13, 17, 32, and 38) epithelial lines and 3T3-NIH (clones 6, 7,
and 9), AKR-2B (clones 10 and 12), and NRK-49F (clones 1 and 3)
fibroblast lines were used. Control wild-type expressing clones (closed
symbols) used for comparison were Mv1Lu-9 and -18, MDCK-1 and -5,
NIH-3T3-2 and -10, AKR-2B clone A105, and NRK-49F-7.