Functional dissection of the intramolecular Src homology 3-guanylate kinase domain coupling in voltage-gated Ca2+ channel beta-subunits.
The beta-subunit of voltage-gated Ca(2+) channels is essential for trafficking the channels to the plasma membrane and regulating their gating. It contains a Src homology 3 (SH3) domain and a guanylate kinase (GK) domain, which interact intramolecularly. We investigated the structural underpinnings of this intramolecular coupling and found that in addition to a previously described SH3 domain beta strand, two structural elements are crucial for maintaining a strong and yet potentially modifiable SH3-GK intramolecular coupling: an intrinsically weak SH3-GK interface and a direct connection of the SH3 and GK domains. Alterations of these elements uncouple the two functions of the beta-subunit, degrading its ability to regulate gating while leaving its chaperone effect intact.
Department of Biological Sciences, 917 Fairchild Center, MC2462, Columbia University, New York, NY 10027, USA.
Yu-hang
YH
Chen
Lin-ling
LL
He
Douglas R
DR
Buchanan
Yun
Y
Zhang
Aileen
A
Fitzmaurice
Jian
J
Yang
D019943:Amino Acid Substitution; D000818:Animals; D020864:Calcium Channels, N-Type / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005260:Female; D051528:Guanylate Kinases / Q000737:chemistry; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009865:Oocytes / Q000378:metabolism; D018408:Patch-Clamp Techniques; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014981:Xenopus; D018909:src Homology Domains
D020864:Calcium Channels, N-Type; D051528:Guanylate Kinases; D021122:Protein Subunits; D011994:Recombinant Proteins