Effect of Mutations in the HA Transmembrane Domain on the Delivery of the Protein to the Apical Surface of MDCK Cells
| Protein . | . | Average percent apical . | . | Number of experiments . | . | Percent insoluble in Triton X-100 . | . | Number of experiments . |
|---|---|---|---|---|---|---|---|---|
| HA | 73 ± 3 | 3 | 38 ± 9 | 3 | ||||
| 4A507 | 51 ± 2 | 5 | 2, 1 | 2 | ||||
| 4A511 | 46 ± 6 | 3 | 3, 3 | 2 | ||||
| 2A511 | 45 ± 4 | 3 | 3 ± 2 | 3 | ||||
| 2A517 | 61 ± 2 | 4 | 2 ± 1 | 3 | ||||
| 4A520 | 31 ± 6 | 4 | 4, 2 | 2 | ||||
| 2A520 | 19 ± 8 | 5 | 2, 2 | 2 | ||||
| 4A524 | 30 | 2 | 18, 9 | 2 | ||||
| 4A528 | 42 ± 2 | 3 | 26, 18 | 2 | ||||
| 5A531 | 77 ± 8 | 5 | 37 ± 3 | 3 | ||||
| A516S | 50 ± 7 | 4 | 38 ± 3 | 4 | ||||
| G520S | 51 ± 10 | 4 | 25, 22 | 2 | ||||
| S521A | 33 ± 2 | 3 | 3, 3 | 2 | ||||
| ΔG520ΔS521 | 32 ± 7 | 3 | 7, 5 | 2 |
| Protein . | . | Average percent apical . | . | Number of experiments . | . | Percent insoluble in Triton X-100 . | . | Number of experiments . |
|---|---|---|---|---|---|---|---|---|
| HA | 73 ± 3 | 3 | 38 ± 9 | 3 | ||||
| 4A507 | 51 ± 2 | 5 | 2, 1 | 2 | ||||
| 4A511 | 46 ± 6 | 3 | 3, 3 | 2 | ||||
| 2A511 | 45 ± 4 | 3 | 3 ± 2 | 3 | ||||
| 2A517 | 61 ± 2 | 4 | 2 ± 1 | 3 | ||||
| 4A520 | 31 ± 6 | 4 | 4, 2 | 2 | ||||
| 2A520 | 19 ± 8 | 5 | 2, 2 | 2 | ||||
| 4A524 | 30 | 2 | 18, 9 | 2 | ||||
| 4A528 | 42 ± 2 | 3 | 26, 18 | 2 | ||||
| 5A531 | 77 ± 8 | 5 | 37 ± 3 | 3 | ||||
| A516S | 50 ± 7 | 4 | 38 ± 3 | 4 | ||||
| G520S | 51 ± 10 | 4 | 25, 22 | 2 | ||||
| S521A | 33 ± 2 | 3 | 3, 3 | 2 | ||||
| ΔG520ΔS521 | 32 ± 7 | 3 | 7, 5 | 2 |
Results are shown from pulse-chase experiments on MDCK cells permanently expressing various HA mutants. Arrival at the apical cell surface was measured by adding trypsin to the chase medium on either the apical or basolateral side of the cell to convert HA into its HA1 and HA2 subunits. The percentage of HA arriving at the apical surface was calculated by dividing fraction of HA cleaved to HA1 and HA2 when trypsin was present at the apical side of the monolayer by the fraction cleaved by trypsin present on both sides of the monolayer. Values are averages from three or more independent experiments and are presented with standard deviations. The fraction of each mutant that was insoluble when cells were lysed in Triton X-100 was determined in parallel experiments. For three or more experiments the average value with standard deviation is presented. Individual values are shown for pairs of experiments.