PMID:17360593

Citation	Nishida, K, Yagisawa, F, Kuroiwa, H, Yoshida, Y and Kuroiwa, T (2007) WD40 protein Mda1 is purified with Dnm1 and forms a dividing ring for mitochondria before Dnm1 in Cyanidioschyzon merolae. Proc. Natl. Acad. Sci. U.S.A. 104:4736-41
Abstract	Mitochondria are not produced de novo but are maintained by division. Mitochondrial division is a coordinated process of positioning and constriction of the division site and fission of double membranes, in which dynamin-related protein is believed to mediate outer membrane fission. Part of the mitochondrial division machinery was purified from M phase-arrested Cyanidioschyzon merolae cells through biochemical fractionation. The dynamin-related protein Dnm1 was one of the two major proteins in the purified fraction and was accompanied by a newly identified protein CMR185C, named Mda1. Mda1 contained a predictable coiled-coil region and WD40 repeats, similarly to Mdv1 and Caf4 in yeasts. Immunofluorescence and immunoelectron microscopy showed that Mda1 localizes as a medial belt or ring on the mitochondrial outer surface throughout the division. The ring formation of Mda1 followed the plane of the ring of FtsZ, a protein that resides in the matrix. Dnm1 consistently colocalized with Mda1 only in the late stages of division. Mda1 protein was expressed through S to M phases and was phosphorylated specifically in M phase when Mda1 transformed from belt into foci and became colocalizing with Dnm1. Dephosphorylation of Mda1 in vitro increased its sedimentation coefficient, suggesting conformational changes of the macromolecule. Disassembly of the purified mitochondrial division machinery was performed by adding GTP to independently release Dnm1, suggesting that Mda1 forms a stable homo-oligomer by itself as a core structure of the mitochondrial division machinery.
Links	PubMed PMC1838669 Online version:10.1073/pnas.0609364104
Keywords	Arabidopsis Proteins; Guanosine Triphosphate/chemistry; Intracellular Signaling Peptides and Proteins/chemistry; Intracellular Signaling Peptides and Proteins/physiology; Microscopy, Fluorescence; Microscopy, Immunoelectron; Mitochondria/metabolism; Phosphorylation; Plant Proteins/chemistry; Plant Proteins/physiology; Protein Binding; Protein Structure, Tertiary; Rhodophyta/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CYAME:A4L9S2	Colocalizes with	GO:0005741: mitochondrial outer membrane	ECO:0000314:		C		Fig. 1D, 3A and E	complete CACAO 10993
CYAME:Q84Y91	Colocalizes with	GO:0005737: cytoplasm	ECO:0000314:		C		Figure 2K,L	complete CACAO 11005
CYAME:Q9SSV6		GO:0031315: extrinsic component of mitochondrial outer membrane	ECO:0000314:		C		Figure 2 A-H, M-P	complete CACAO 11006

References

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