Figure 8.

Support for heterodimer formation and function in COS cells. (A) Immunofluorescence micrograph showing a blockade of transferrin uptake (green perinuclear staining) in cells overexpressing Amph1 (stained red) or Myc-Amph2 (stained blue). The mauve cell marked with an arrow is cotransfected with both constructs (and therefore overexpressing both isoforms) and takes up transferrin normally. The transferrin uptake assay was done according to Wigge et al. (1997). (B) Quantitation of the effect. Sixty cells (20 from each category) were measured for transferrin uptake and the mean value was expressed as a percentage of normal transferrin uptake (i.e., that of untransfected cells).