Fission yeast Dma1 requires RING domain dimerization for its ubiquitin ligase activity and mitotic checkpoint function.
In fission yeast (Schizosaccharomyces pombe), the E3 ubiquitin ligase Dma1 delays cytokinesis if chromosomes are not properly attached to the mitotic spindle. Dma1 contains a C-terminal RING domain, and we have found that the Dma1 RING domain forms a stable homodimer. Although the RING domain is required for dimerization, residues in the C-terminal tail are also required to help form or stabilize the dimeric structure because mutation of specific residues in this region disrupts Dma1 dimerization. Further analyses showed that Dma1 dimerization is required for proper localization at spindle pole bodies and the cell division site, E3 ligase activity, and mitotic checkpoint function. Thus, Dma1 forms an obligate dimer via its RING domain, which is essential for efficient transfer of ubiquitin to its substrate(s). This study further supports the mechanistic paradigm that many RING E3 ligases function as RING dimers.
Howard Hughes Medical Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
Alyssa E
AE
Johnson
Scott E
SE
Collier
Melanie D
MD
Ohi
Kathleen L
KL
Gould
D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D059566:M Phase Cell Cycle Checkpoints; D008938:Mitosis; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D021381:Protein Transport; D054829:RING Finger Domains; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000502:physiology; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D008941:Spindle Apparatus / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D018797:Cell Cycle Proteins; C103134:Dma1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D044767:Ubiquitin-Protein Ligases