Table II.
Relative Myristoylation Levels of Wild-Type and Mutant Fyn Constructs in COS-1 Cells
| Construct | 125I-IC13 incorporation per 35S-labeled unit of Fyn protein | |||||||
|---|---|---|---|---|---|---|---|---|
| 35S-Met | 125I-IC13 | 125I-IC13/35S-Met | n | |||||
| Fyn | 100% | 100% | 100% | 8 | ||||
| G2A-Fyn | 87 ± 5 | 1 ± 1 | 0 | 2 | ||||
| K7A-Fyn | 145 ± 8 | 73 ± 6 | 49 ± 2 | 2 | ||||
| K9A-Fyn | 195 ± 6 | 116 ± 8 | 60 ± 4 | 2 | ||||
| K7,9A-Fyn | 160 ± 12 | 28 ± 6 | 17 ± 3 | 5 | ||||
| Lck(10)Fyn | 125 ± 3 | 104 ± 3 | 91 ± 3 | 2 | ||||
COS-1 cells were transfected with Fyn cDNA as indicated and radiolabeled as described in Fig. 1. Gels were exposed to PhosphorImager screens for 24 or 48 h, and incorporation of Tran35S-label or 125I-IC13 into wild-type and mutant Fyn was measured using the ImageQuant software provided with the PhosphorImager system. Values for 35S-label in Fyn ranged from 50,000 to 200,000 PhosphorImager units, and for 125I-labeled Fyn from 10,000 to 50,000 units. Background numbers comprised 5–10% of total values for both labeling procedures. Incorporation of radiolabel into the Fyn constructs is expressed relative to wild type. n, number of experiments performed for each construct.