Caveolin-3 and SAP97 form a scaffolding protein complex that regulates the voltage-gated potassium channel Kv1.5
Eduardo J Folco1, Gong-Xin Liu, Gideon Koren
1Bioelectricity Laboratory, Cardiovascular Division, Brigham and Women's Hospital, Boston, MA 02115, USA.
Abstract:
The targeting of ion channels to particular membrane microdomains and their organization in macromolecular complexes allow excitable cells to respond efficiently to extracellular signals. In this study, we describe the formation of a complex that contains two scaffolding proteins: caveolin-3 (Cav-3) and a membrane-associated guanylate kinase (MAGUK), SAP97. Complex formation involves the association of Cav-3 with a segment of SAP97 localized between its PDZ2 and PDZ3 domains. In heterologous expression systems, this scaffolding complex can recruit Kv1.5 to form a tripartite complex in which each of the three components interacts with the other two. These interactions regulate the expression of currents encoded by a glycosylation-deficient mutant of Kv1.5. We conclude that the association of Cav-3 with SAP97 may constitute the nucleation site for the assembly of macromolecular complexes containing potassium channels.
Related Concept Videos
Voltage-gated Ion Channels
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Voltage-gated Ion Channels
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Clathrin Coated Vesicles
Overview of Secretory Vesicles
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
ATP Driven Pumps III: V-type Pumps
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...
Coat Assembly and GTPases
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...


