Protein kinase modulation of a neuronal cation channel requires protein-protein interactions mediated by an Src homology 3 domain.
Accumulating evidence suggests that many ion channels reside within a multiprotein complex that contains kinases and other signaling molecules. The role of the adaptor proteins that physically link these complexes together for the purposes of ion channel modulation, however, has been little explored. Here, we examine the protein-protein interactions required for regulation of an Aplysia bag cell neuron cation channel by a closely associated protein kinase C (PKC). In inside-out patches, the PKC-dependent enhancement of cation channel open probability could be prevented by the src homology 3 (SH3) domain, presumably by disrupting a link between the channel and the kinase. SH3 and PDZ domains from other proteins were ineffective. Modulation was also prevented by an SH3 motif peptide that preferentially binds the SH3 domain of src. Furthermore, whole-cell depolarizations elicited by cation channel activation were decreased by the src SH3 domain. These data suggest that the cation channel-PKC association may require SH3 domain-mediated interactions to bring about modulation, promote membrane depolarization, and initiate prolonged changes in bag cell neuron excitability. In general, protein-protein interactions between ion channels and protein kinases may be a prominent mechanism underlying neuromodulation.
Magoski
Neil S
NS
Department of Pharmacology, Yale University, New Haven, Connecticut 06520, USA.
Wilson
Gisela F
GF
Kaczmarek
Leonard K
LK
D000255:Adenosine Triphosphate / Q000494:pharmacology; D020816:Amino Acid Motifs / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia; D002412:Cations / Q000378:metabolism*; D002478:Cells, Cultured; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D046911:Macromolecular Substances; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism*; D018909:src Homology Domains / Q000502:physiology
D002412:Cations; D007473:Ion Channels; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; D010455:Peptides; D000255:Adenosine Triphosphate; D011493:Protein Kinase C