Referenced in: none

Automatically associated channels: Kv1.4 , Kv3.1 , Kv4.2

Title: Molecular cloning and characterization of CALP/KChIP4, a novel EF-hand protein interacting with presenilin 2 and voltage-gated potassium channel subunit Kv4.

Authors: Yuichi Morohashi, Noriyuki Hatano, Susumu Ohya, Rie Takikawa, Tomonari Watabiki, Nobumasa Takasugi, Yuji Imaizumi, Taisuke Tomita, Takeshi Iwatsubo

Journal, date & volume: J. Biol. Chem., 2002 Apr 26 , 277, 14965-75

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/11847232

Abstract
Presenilin (PS) genes linked to early-onset familial Alzheimer's disease encode polytopic membrane proteins that are presumed to constitute the catalytic subunit of gamma-secretase, forming a high molecular weight complex with other proteins. During our attempts to identify binding partners of PS2, we cloned CALP (calsenilin-like protein)/KChIP4, a novel member of calsenilin/KChIP protein family that interacts with the C-terminal region of PS. Upon co-expression in cultured cells, CALP was directly bound to and co-localized with PS2 in endoplasmic reticulum. Overexpression of CALP did not affect the metabolism or stability of PS complex, and gamma-cleavage of betaAPP or Notch site 3 cleavage was not altered. However, co-expression of CALP and a voltage-gated potassium channel subunit Kv4.2 reconstituted the features of A-type K(+) currents and CALP directly bound Kv4.2, indicating that CALP functions as KChIPs that are known as components of native Kv4 channel complex. Taken together, CALP/KChIP4 is a novel EF-hand protein interacting with PS as well as with Kv4 that may modulate functions of a subset of membrane proteins in brain.