FIG. 1.

Expression of RET mutants in Cos cells. (Top) Scheme of the short isoform of the RET protein (35). SP, signal peptide; CAD, cadherin-like domain; CYS, cysteine-rich tract; TM, transmembrane region; TK, tyrosine kinase domain; 1072, the number of amino acids in the protein. The positions of the mutants analyzed are also shown. (A and B) Cos 7 cells were transfected with 5 μg of each RET construct. Forty-eight hours later, cells were harvested and protein extracts were prepared. Equal amounts of proteins (100 μg) from the transfectants (indicated above the lanes) were loaded in each lane and fractionated on an SDS–7.5% PAGE gel. After transfer, the proteins were detected by using anti-RET antibodies. The migration of the mature and immature RET forms is indicated on the side.