DAP-like kinase, a member of the death-associated protein kinase family, associates with centrosomes, centromers, and the contractile ring during mitosis

• Published in: European journal of cell biology Vol. 82; no. 9; pp. 447 - 459
• Main Authors: Preuss, Ute, Bierbaum, Hanna, Buchenau, Peter, Scheidtmann, Karl Heinz
• Format: Journal Article
• Language: English
• Published: Germany Elsevier GmbH 01-09-2003; Elsevier Science Ltd
• Subjects: Actins - metabolism; Animals; Antigens - metabolism; Apoptosis - physiology; Apoptosis Regulatory Proteins; Calcium-Calmodulin-Dependent Protein Kinases; Carrier Proteins - metabolism; Cell Nucleus - metabolism; Cells, Cultured; Centromere - metabolism; centromeres; Centrosome - metabolism; centrosomes; contractile ring; cytokinesis; Cytoskeleton - metabolism; Death-Associated Protein Kinases; Dlk/ZIP kinase; Green Fluorescent Proteins; Humans; Interphase - physiology; Intracellular Signaling Peptides and Proteins; Luminescent Proteins; MAP Kinase Kinase Kinases; Microscopy, Fluorescence; mitosis; Mitosis - physiology; Phosphorylation; Protein-Serine-Threonine Kinases - metabolism; Rats; Spindle Apparatus - metabolism; Tubulin - metabolism; centrosomes; centromeres; contractile ring; mitosis; cytokinesis; Dlk/ZIP kinase
• ISSN: 0171-9335; 1618-1298
• DOI: 10.1078/0171-9335-00332

DAP-like kinase (Dlk) is a nuclear serine/threonine-specific kinase which has been implicated in apoptosis. However, induction of apoptosis by Dlk requires its relocation to the cytoplasm, particularly association with the actin cytoskeleton, which is achieved through interaction with pro-apoptotic protein Par-4. On the other hand, nuclear Dlk does not induce apoptosis and has rather been implicated in transcription. To further explore the biological functions of Dlk, we established a cell clone of MCF-7 cells stably expressing a GFP-Dlk fusion protein at low level. Ectopic expression of GFP-Dlk did not affect the growth properties of the cells. During interphase, GFP-Dlk showed a diffuse nuclear distribution with punctate staining in a subpopulation of cells. During mitosis, however, Dlk was associated with centrosomes, centromeres, and the contractile ring, but not with the mitotic spindle. Association with centrosomes, as confirmed by colocalization with γ-tubulin and pericentrin persisted throughout mitosis but was also seen in interphase cells. Interestingly, GFP-Dlk and γ-tubulin could be co-immunoprecipitated indicating that they are present in the same protein complex. Association of Dlk with centromeres, as verified by confocal fluorescence microscopy with centromere-specific antibodies was more restricted and discernable from prophase to early anaphase. Centromere association of Dlk coincides with H3 phosphorylation at Thr11 that is specifically phosphorylated by Dlk in vitro (U. Preuss, G. Landsberg, K. H. Scheidtmann, Nucleic Acids Res. 31, 878 – 885, 2003). During cytokinesis, Dlk was enriched in the contractile acto-myosin ring and colocalized with Ser19-phosphorylated myosin light chain, which is an in vitro substrate of Dlk. Strikingly, a C-terminal truncation mutant of Dlk generated multi-nucleated cells. Together, these data suggest that Dlk participates in regulation and, perhaps, coordination of mitotis and cytokinesis.