A tctex1-Ca2+ channel complex for selective surface expression of Ca2+ channels in neurons.
Voltage-gated Ca(2+) channels (VGCCs) are important in regulating a variety of cellular functions in neurons. It remains poorly understood how VGCCs with different functions are sorted within neurons. Here we show that the t-complex testis-expressed 1 (tctex1) protein, a light-chain subunit of the dynein motor complex, interacts directly and selectively with N- and P/Q-type Ca(2+) channels, but not L-type Ca(2+) channels. The interaction is insensitive to Ca(2+). Overexpression in hippocampal neurons of a channel fragment containing the binding domain for tctex1 significantly decreases the surface expression of endogenous N- and P/Q-type Ca(2+) channels but not L-type Ca(2+) channels, as determined by immunostaining. Furthermore, disruption of the tctex1-Ca(2+) channel interaction significantly reduces the Ca(2+) current density in hippocampal neurons. These results underscore the importance of the specific tctex1-channel interaction in determining sorting and trafficking of neuronal Ca(2+) channels with different functionalities.
Lai
Meizan
M
Department of Pharmacology, University of Pennsylvania School of Medicine, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104, USA.
Wang
Fushun
F
Rohan
Joyce G
JG
Maeno-Hikichi
Yuka
Y
Chen
Yuan
Y
Zhou
Yi
Y
Gao
Guangping
G
Sather
William A
WA
Zhang
Ji-fang
JF
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002118:Calcium / Q000494:pharmacology; D015220:Calcium Channels / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D002234:Carbodiimides / Q000378:metabolism / Q000494:pharmacology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004398:Dyneins; D025802:Electric Capacitance; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology; D007150:Immunohistochemistry / Q000379:methods; D047468:Immunoprecipitation / Q000379:methods; D015640:Ion Channel Gating; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D018408:Patch-Clamp Techniques / Q000379:methods; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013997:Time Factors; D014162:Transfection / Q000379:methods; D020798:Two-Hybrid System Techniques; D056427:t-Complex Genome Region
D015220:Calcium Channels; D002234:Carbodiimides; C533388:Dynlt1 protein, rat; D004791:Enzyme Inhibitors; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; C038088:N-cyclohexyl-N'-(4-dimethylamino-alpha-naphthyl)carbodiimide; D004398:Dyneins; D002118:Calcium