The kinesin-like motor protein KIF1C occurs in intact cells as a dimer and associates with proteins of the 14-3-3 family.
Proteins of the kinesin superfamily are regulated in their motor activity as well as in their ability to bind to their cargo by carboxyl-terminal associating proteins and phosphorylation. KIF1C, a recently identified member of the KIF1/Unc104 family, was shown to be involved in the retrograde vesicle transport from the Golgi-apparatus to the endoplasmic reticulum. In a yeast two-hybrid screen using the carboxyl-terminal 350 amino acids of KIF1C as a bait, we identified as binding proteins 14-3-3 beta, gamma, epsilon, and zeta. In addition, a clone encoding the carboxyl-terminal 290 amino acids of KIF1C was found, indicating a potential for KIF1C to dimerize. Subsequent transient overexpression experiments showed that KIF1C can dimerize efficiently. However, in untransfected cells, only a small portion of KIF1C was detected as a dimer. The association of 14-3-3 proteins with KIF1C could be confirmed in transient expression systems and in untransfected cells and was dependent on the phosphorylation of serine 1092 located in a consensus binding sequence for 14-3-3 ligands. Serine 1092 was a substrate for the protein kinase casein kinase II in vitro, and inhibition of casein kinase II in cells diminished the association of KIF1C with 14-3-3gamma. Our data thus suggest that KIF1C can form dimers and is associated with proteins of the 14-3-3 family.
Dorner
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C
Medical Clinic IV, University of Tübingen, Tübingen, 72076 Germany.
Ullrich
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A
Häring
H U
HU
Lammers
R
R
D048948:14-3-3 Proteins; D000818:Animals; D001665:Binding Sites; D047390:Casein Kinase II; D002460:Cell Line; D019281:Dimerization; D006801:Humans; D016547:Kinesins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D013379:Substrate Specificity; D020798:Two-Hybrid System Techniques; D014446:Tyrosine 3-Monooxygenase
D048948:14-3-3 Proteins; C114063:KIF1C protein, human; C485246:Kif1c protein, mouse; D011506:Proteins; D014446:Tyrosine 3-Monooxygenase; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D016547:Kinesins