![]() ![]() Finally, co-immunoprecipitation experiments demonstrated associations between KCa3.1, VAMP3, SNAP-23 and STX-4. Also, knockdown of STX-4 lowered the BLM expression of KCa3.1 by 54 ± 6% (p ≤ 0.05, n = 5) and reduced KCa3.1 current by 78 ± 11% (p ≤ 0.05, n = 5). Similarly, siRNA knockdown of SNAP-23 reduced the expression of KCa3.1 at the BLM by 56 ± 7% (p ≤ 0.01, n = 6) and reduced KCa3.1 current by 80 ± 11% (p ≤ 0.05, n = 6). Measurements of BLM-localized KCa3.1 currents, in Ussing chambers, demonstrated knockdown of VAMP3 reduced KCa3.1 current by 70 ± 4% (p ≤ 0.05, n = 5). siRNA-mediated knockdown of VAMP3 reduced BLM expression of KCa3.1 by 57 ± 5% (p ≤ 0.05, n = 5). ![]() ![]() We carried out immunoblot, siRNA and Ussing chamber experiments on FRT cells, stably expressing KCa3.1-BLAP/Bir-A-KDEL, grown as high-resistance monolayers. Here, we examine the role of the SNARE proteins VAMP3, SNAP-23 and syntaxin 4 (STX-4) in the targeting of KCa3.1 to the BLM of Fischer rat thyroid (FRT) epithelial cells. We previously reported that targeting of KCa3.1 to the BLM of epithelial cells is Myosin-Vc-, Rab1-and Rab8-dependent. Surprisingly, the mechanism of KCa3.1 membrane targeting is poorly understood. KCa3.1, a calcium-activated, intermediate-conductance potassium channel, is targeted to the basolateral membrane (BLM) in epithelial cells. Targeting proteins to a specific membrane is crucial for proper epithelial cell function.
0 Comments
Leave a Reply. |