Table 1.

Polarized surface distribution and Triton X-100 insolubility of chimeric and mutant proteinsa

Construct no.ProteinNo. of exptsAvg amt of apically transported protein ± SD (%)No. of exptsAvg amt of TX-100-insoluble protein ± SD (%)
1TR418 ± 458 ± 3
2TRΔ57449 ± 3519 ± 4
3NATR578 ± 4460 ± 3
4NA(gs)TR474 ± 3544 ± 3
53/4TR1/4NA449 ± 2415 ± 2
61/4NA3/4TR461 ± 5425 ± 6
71/3TR2/3NA359 ± 2535 ± 4
83/4NA1/4TR374 ± 5430 ± 4
9NA4A7474 ± 2532 ± 2
10NA5A11520 ± 5520 ± 6
11NA5A14477 ± 4554 ± 3
12NA4A19561 ± 5531 ± 4
13NA4A23321 ± 4320 ± 5
14NA5A27369 ± 2422 ± 4
15NA5A31320 ± 358 ± 4
  • a Confluent monolayers of MDCK cell lines were grown on filters, induced with CdCl2, pulse-labeled, and chased (Fig. 3 and 4). For polarized surface distribution, apical and basolateral surface proteins were biotinylated, isolated by anti-TR antibodies, analyzed by SDS-PAGE, autoradiographed, and quantified as described in Materials and Methods. For TX-100 insolubility, cells were extracted on ice with extraction buffer containing 1% TX-100 for 10 min and insoluble and soluble proteins were precipitated with anti-TR antibodies, analyzed by SDS-PAGE, and quantified as described in Materials and Methods.