Identification and functional characterization of cereblon as a binding protein for large-conductance calcium-activated potassium channel in rat brain.
Large-conductance Ca2+-activated K+ (BK(Ca)) channels are activated by membrane depolarization and modulated by intracellular Ca2+. Here, we report the direct interaction of cereblon (CRBN) with the cytosolic carboxy-terminus of the BK(Ca) channel alpha subunit (Slo). Rat CRBN contained the N-terminal domain of the Lon protease, a 'regulators of G protein-signaling' (RGS)-like domain, a leucine zipper (LZ) motif, and four putative protein kinase C (PKC) phosphorylation sites. RNA messages of rat cereblon (rCRBN) were widely distributed in different tissues with especially high-levels of expression in the brain. Direct association of rCRBN with the BK(Ca) channel was confirmed by immunoprecipitation in brain lysate, and the two proteins were co-localized in cultured rat hippocampal neurons. Ionic currents evoked by the rSlo channel were dramatically suppressed upon coexpression of rCRBN. rCRBN decreased the formation of the tetrameric rSlo complex thus reducing the surface expression of functional channels. Therefore, we suggest that CRBN may play an important role in assembly and surface expression of functional BK(Ca) channels by direct interaction with the cytosolic C-terminus of its alpha-subunit.
Jo
Sooyeon
S
Department of Life Science, Gwangju Institute Science and Technology (GIST), Gwangju, Republic of Korea.
Lee
Kwang-Hee
KH
Song
Sungmin
S
Jung
Yong-Keun
YK
Park
Chul-Seung
CS
D049069:ATP-Dependent Proteases; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D002460:Cell Line; D004274:DNA, Recombinant; D014644:Genetic Variation; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated / Q000235:genetics / Q000378:metabolism*; D000081033:Potassium Channels, Sodium-Activated; D017434:Protein Structure, Tertiary / Q000502:physiology; D020710:RGS Proteins / Q000502:physiology; D051381:Rats; D014018:Tissue Distribution; D020798:Two-Hybrid System Techniques; D043743:Ubiquitin-Protein Ligase Complexes; D015003:Yeasts
C503910:CRBN protein, rat; D002352:Carrier Proteins; D004274:DNA, Recombinant; C494842:Kcnma1 protein, rat; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D051036:Large-Conductance Calcium-Activated Potassium Channels; D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D000081033:Potassium Channels, Sodium-Activated; D020710:RGS Proteins; C000626167:kcnt1 protein, rat; D043743:Ubiquitin-Protein Ligase Complexes; D049069:ATP-Dependent Proteases