Traffic of Kv4 K channels mediated by KChlP1 is via a novel post-ER vesicular pathway.

Hasdemir, Burcu; Fitzgerald, Daniel J.; Prior, Ian A.; Tepikin, Alexei V.; Burgoyne, Robert D.

The traffic of Kv4 K channels is regulated by the potassium channel interacting proteins (KChlPs). Kv4.2 expressed alone was not retained within the ER, but reached the Golgi complex. Coexpression of KChlP1 resulted in traffic of the channel to the plasma membrane, and traffic was abolished when mutations were introduced into the EF-hands with channel captured on vesicular structures that colocalized with KChlP1 (2-4)-EYFP. The EF-hand mutant had no effect on general exocytic traffic. Traffic of Kv4.2 was coat protein complex I (COPI)-dependent, but KChlP1-containing vesicles were not COPII-coated, and expression of a GTP-loaded Sar1 mutant to block COPII function more effectively inhibited traffic of vesicular stomatitis virus glycoprotein (VSVG) than did KChlF1/Kv4.2 through the secretory pathway. Therefore, KChlP1 seems to be targeted to post-ER transport vesicles, different from COPII-coated vesicles and those involved in traffic of VSVG. When expressed in hippocampal neurons, KChlP1 co-distributed with dendritic Golgi outposts; therefore, the KChlP1 pathway could play an important role in local vesicular traffic in neurons.

POTASSIUM channels; PROTEINS; CELL membranes; GENETIC mutation; COATED vesicles

Journal of Cell Biology, 2005, Vol 171, Issue 3, p458

0021-9525

Academic Journal

10.1083/jcb.200506005