Monomeric 14-3-3 protein is sufficient to modulate the activity of the Drosophila slowpoke calcium-dependent potassium channel.
Drosophila 14-3-3zeta (D14-3-3zeta) modulates the activity of the Slowpoke calcium-dependent potassium channel (dSlo) by interacting with the dSlo binding protein, Slob. We show here that D14-3-3zeta forms dimers in vitro. Site-directed mutations in its putative dimerization interface result in a dimerization-deficient form of D14-3-3zeta. Both the wild-type and dimerization-deficient forms of D14-3-3zeta bind to Slob with similar affinity and form complexes with dSlo. When dSlo and Slob are expressed in mammalian cells, the dSlo channel activity is similarly modulated by co-expression of either the wild-type or the dimerization-deficient form of D14-3-3zeta. In addition, dSlo is still modulated by wild-type D14-3-3zeta in the presence of a 14-3-3 mutant, which does not itself bind to Slob but forms heterodimers with the wild-type 14-3-3. These data, taken together, suggest that monomeric D14-3-3zeta is capable of modulating dSlo channel activity in this regulatory complex.
Zhou
Yi
Y
Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia 19104, USA. yizhou@mail.med.upenn.edu
Reddy
Smitha
S
Murrey
Heather
H
Fei
Hong
H
Levitan
Irwin B
IB
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D000818:Animals; D019281:Dimerization; D004330:Drosophila; D029721:Drosophila Proteins; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008969:Molecular Sequence Data; D024681:Potassium Channels, Calcium-Activated / Q000502:physiology*; D014446:Tyrosine 3-Monooxygenase / Q000737:chemistry* / Q000502:physiology*
D048948:14-3-3 Proteins; D029721:Drosophila Proteins; D051036:Large-Conductance Calcium-Activated Potassium Channels; D024681:Potassium Channels, Calcium-Activated; C494844:slo protein, Drosophila; D014446:Tyrosine 3-Monooxygenase