A dynamically regulated 14-3-3, Slob, and Slowpoke potassium channel complex in Drosophila presynaptic nerve terminals.
Slob is a novel protein that binds to the carboxy-terminal domain of the Drosophila Slowpoke (dSlo) calcium-dependent potassium (K(Ca)) channel. A yeast two-hybrid screen with Slob as bait identifies the zeta isoform of 14-3-3 as a Slob-binding protein. Coimmunoprecipitation experiments from Drosophila heads and transfected cells confirm that 14-3-3 interacts with dSlo via Slob. All three proteins are colocalized presynaptically at Drosophila neuromuscular junctions. Two serine residues in Slob are required for 14-3-3 binding, and the binding is dynamically regulated in Drosophila by calcium/calmodulin-dependent kinase II (CaMKII) phosphorylation. 14-3-3 coexpression dramatically alters dSlo channel properties when wild-type Slob is present but not when a double serine mutant Slob that is incapable of binding 14-3-3 is present. The results provide evidence for a dSlo/Slob/14-3-3 regulatory protein complex.
Zhou
Y
Y
Department of Biochemistry, Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454, USA.
Schopperle
W M
WM
Murrey
H
H
Jaramillo
A
A
Dagan
D
D
Griffith
L C
LC
Levitan
I B
IB
D048948:14-3-3 Proteins; D000818:Animals; D002118:Calcium / Q000502:physiology; D004330:Drosophila / Q000502:physiology*; D029721:Drosophila Proteins; D006824:Hybridization, Genetic; D019476:Insect Proteins / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000502:physiology; D009469:Neuromuscular Junction / Q000502:physiology; D010766:Phosphorylation; D015221:Potassium Channels / Q000502:physiology; D017729:Presynaptic Terminals / Q000502:physiology; D011506:Proteins / Q000502:physiology; D014446:Tyrosine 3-Monooxygenase
D048948:14-3-3 Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D011506:Proteins; C111538:Slob protein, Drosophila; D014446:Tyrosine 3-Monooxygenase; D002118:Calcium