Kv channel-interacting proteins as neuronal and non-neuronal calcium sensors.

["Kv channel-interacting proteins (KChIPs) belong to the neuronal calcium sensor (NCS) family of Ca-binding EF-hand proteins. KChIPs constitute a group of specific auxiliary \u03b2-subunits for Kv4 channels, the molecular substrate of transient potassium currents in both neuronal and non-neuronal tissues. Moreover, KChIPs can interact with presenilins to control ER calcium signaling and apoptosis, and with DNA to control gene transcription. Ca binding via their EF-hands, with the consequence of conformationl changes, is well documented for KChIPs. Moreover, the Ca dependence of the presenilin\/KChIP complex may be related to Alzheimer's disease and the Ca dependence of the DNA\/KChIP complex to pain sensing. However, only in few cases could the Ca binding to KChIPs be directly linked to the control of excitability in nerve and muscle cells known to express Kv4\/KChIP channel complexes. This review summarizes current knowledge about the Ca binding properties of KChIPs and the Ca dependencies of macromolecular complexes containing KChIPs, including those with presenilins, DNA and especially Kv4 channels. The respective physiological or pathophysiolgical roles of Ca binding to KChIPs are discussed."]