14 ‐3‐3 proteins regulate K2P5.1 surface expression on T lymphocytes

ABSTRACT
K2P5.1 channels (also called TASK‐2 or KCNK5) have already been shown to be relevant in the pathophysiology of autoimmune disease since they are known to be upregulated on peripheral and central T lymphocytes of multiple sclerosis (MS) patients. Moreover, overexpression of K2P5.1 channels in vitro provokes enhanced T‐cell effector functions. However, the molecular mechanisms regulating intracellular K2P5.1 channel trafficking are unknown so far. Thus, the aim of the study is to elucidate the trafficking of K2P5.1 channels on T lymphocytes. Using mass spectrometry analysis, we have identified 14‐3‐3 proteins as novel binding partners of K2P5.1 channels. We show that a non‐classical 14‐3‐3 consensus motif (R‐X‐X‐pT/S‐x) at the channel's C‐terminus allows the binding between K2P5.1 and 14‐3‐3. The mutant K2P5.1/S266A diminishes the protein‐protein interaction and reduces the amplitude of membrane currents. Application of a non‐peptidic 14‐3‐3 inhibitor (BV02) significantly reduces the number of wild type channels in the plasma membrane, whereas the drug has no effect on the trafficking of the mutated channel. Furthermore, blocker application reduces T‐cell effector functions. Taken together, we demonstrate that 14‐3‐3 interacts with K2P5.1 and plays an important role in channel trafficking.

Synopsis
K2P5.1 channels possess a putative non‐classical consensus motif for 14‐3‐3 proteins that mediates the interaction and promo...

Source: Traffic - September 30, 2016 Category: Research Authors: Juncal Fern ández‐Orth, Petra Ehling, Tobias Ruck, Susann Pankratz, Majella‐Sophie Hofmann, Peter Landgraf, Daniela C. Dieterich, Karl‐Heinz Smalla, Thilo Kähne, Guiscard Seebohm, Thomas Budde, Heinz Wiendl, Stefan Bittner, Sven G. Meuth Tags: Original Article Source Type: research