Dynamin Is a Minibrain Kinase/Dual Specificity Yak1-related Kinase 1A Substrate

• Published in: The Journal of biological chemistry 2002-05, Vol.277 (20), p.17597-17604
• Main Authors: Chen-Hwang, Mo-Chou, Chen, Huey-Ru, Elzinga, Marshall, Hwang, Yu-Wen
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing; amphiphysin 1; Animals; Brain - metabolism; Carrier Proteins - metabolism; dynamin 1; Dynamin I; Dynamins; Dyrk Kinases; Endocytosis - physiology; GRB2 Adaptor Protein; GTP Phosphohydrolases - metabolism; Male; Mnbk/Dyrk1A protein; Molecular Weight; Nerve Tissue Proteins - metabolism; Phosphorylation; Protein Serine-Threonine Kinases - genetics; Protein Serine-Threonine Kinases - isolation & purification; Protein Serine-Threonine Kinases - metabolism; Protein-Tyrosine Kinases - genetics; Protein-Tyrosine Kinases - isolation & purification; Protein-Tyrosine Kinases - metabolism; Proteins - metabolism; Rats; src Homology Domains; Substrate Specificity
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M111101200

The minibrain kinase (Mnbk)/dual specificity Yak 1-related kinase 1A (Dyrk1A) gene is implicated in the mental retardation associated with Down's syndrome. It encodes a proline-directed serine/threonine kinase whose function has yet to be defined. We have used a solid-phase Mnbk/Dyrk1A kinase assay to aid in the search for the cellular Mnbk/Dyrk1A substrates. The assay revealed that rat brain contains two cytosolic proteins, one with a molecular mass of 100 kDa and one with a molecular mass of 140 kDa, that were prominently phosphorylated by Mnbk/Dyrk1A. The 100-kDa protein was purified and identified as dynamin 1. The conclusion was further supported by evidence that a recombinant glutathione S-transferase fusion protein containing dynamin isoform 1aa was phosphorylated by Mnbk/Dyrk1A. In addition to isoform 1aa, Mnbk/Dyrk1A also phosphorylated isoforms 1ab and 2aa but not human MxA protein when analyzed by the solid-phase kinase assay. Upon Mnbk/Dyrk1A phosphorylation, the interaction of dynamin 1 with the Src homology 3 domain of amphiphysin 1 was reduced. However, when Mnbk/Dyrk1A phosphorylation was allowed to proceed more extensively, the phosphorylation enhanced rather than reduced the binding of dynamin 1 to amphiphysin 1. The result suggests that Mnbk/Dyrk1A can play a dual role in regulating the interaction of dynamin 1 with amphiphysin 1. Mnbk/Dyrk1A phosphorylation also reduced the interaction of dynamin with endophilin 1, whereas the same phosphorylation enhanced the binding of dynamin 1 to Grb2. Nevertheless, the dual function of Mnbk/Dyrk1A phosphorylation was not observed for the interaction of dynamin 1 with endophilin 1 or Grb2. The interactions of dynamin with amphiphysin and endophilin are essential for the formation of endocytic complexes; our results suggest that Mnbk/Dyrk1A may function as a regulator controlling the assembly of endocytic apparatus.