Abstract
The human M phase phosphoprotein 1 (MPP1), previously identified through a screening of a subset of proteins specifically phosphorylated at the G2/M transition (Matsumoto-Taniura, N., Pirollet, F., Monroe, R., Gerace, L., and Westendorf, J. M. (1996) Mol. Biol. Cell 7, 1455-1469), is characterized as a plus-end-directed kinesin-related protein. Recombinant MPP1 exhibits in vitro microtubule-binding and microtubule-bundling properties as well as microtubule-stimulated ATPase activity. In gliding experiments using polarity-marked microtubules, MPP1 is a slow molecular motor that moves toward the microtubule plus-end at a 0.07 microm/s speed. In cycling cells, MPP1 localizes mainly to the nuclei in interphase. During mitosis, MPP1 is diffuse throughout the cytoplasm in metaphase and subsequently localizes to the midzone to further concentrate on the midbody. MPP1 suppression by RNA interference induces failure of cell division late in cytokinesis. We conclude that MPP1 is a new mitotic molecular motor required for completion of cytokinesis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / metabolism
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Amino Acid Sequence
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Animals
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Cell Cycle Proteins*
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Cell Division / physiology*
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Cell Line
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Cell Movement
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Cells, Cultured
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Cloning, Molecular
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Cytoplasm / metabolism
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DNA, Complementary / metabolism
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Electrophoresis, Polyacrylamide Gel
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Epitopes
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Flow Cytometry
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G2 Phase
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Gene Library
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Genome
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Green Fluorescent Proteins
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HeLa Cells
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Humans
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Immunoblotting
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Insecta
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Kinesins / metabolism*
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Kinetics
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Luminescent Proteins / metabolism
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Metaphase
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Microscopy, Fluorescence
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Microtubules / metabolism*
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Mitosis
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Molecular Sequence Data
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Mutagenesis, Site-Directed
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Phosphoproteins / metabolism
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Phosphoproteins / physiology*
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Phosphorylation
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Protein Structure, Tertiary
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RNA Interference
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RNA, Small Interfering / metabolism
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Recombinant Fusion Proteins / metabolism
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Recombinant Proteins / metabolism
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Sequence Analysis, DNA
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Sequence Homology, Amino Acid
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Time Factors
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Tissue Distribution
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Transfection
Substances
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Cell Cycle Proteins
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DNA, Complementary
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Epitopes
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Luminescent Proteins
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Phosphoproteins
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RNA, Small Interfering
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Recombinant Fusion Proteins
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Recombinant Proteins
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Green Fluorescent Proteins
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Adenosine Triphosphatases
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KIF20B protein, human
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Kinesins