Osamu Numata

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Actin-depolymerizing factor (ADF)/cofilin is widely expressed in eukaryotes and plays a central role in reorganizing the actin cytoskeleton by disassembling actin filaments. The ADF-homologous domain (ADF-H) is conserved in several other actin-modulating proteins such as twinfilin, Abp1/drebrin, and coactosin. Although these proteins interact with actin via(More)
The contractile ring (CR) consists of bundled actin filaments and myosin II; however, the actin-bundling factor remains elusive. We show that the fission yeast Schizosaccharomyces pombe IQGAP Rng2 is involved in the generation of CR F-actin and required for its arrangement into a ring. An N-terminal fragment of Rng2 is necessary for the function of Rng2 and(More)
  • M Hirono, Y Kumagai, O Numata, Y Watanabe
  • Proceedings of the National Academy of Sciences…
  • 1989
Actin from Tetrahymena pyriformis has been purified by monitoring the presence of the actin gene product with an antiserum against a synthetic N-terminal peptide deduced from the nucleotide sequence of the Tetrahymena actin gene that we cloned previously. This highly purified Tetrahymena actin shares many essential properties with ubiquitous actin,(More)
The Tetrahymena Ca(2+)-binding protein of 25 kDa (TCBP-25) is a member of the calmodulin family containing four EF-hand Ca(2+)-binding loops, but its biological role has not yet been investigated. In this study, TCBP-25 was expressed in Escherichia coli as a glutathione S-transferase fusion protein and then purified. Purified TCBP-25 showed a typical(More)
Small GTPase Rab (products of ras genes from rat brain) is a widely conserved molecular switch among eukaryotes and regulates membrane trafficking pathways. It is generally considered that the number of Rab encoded in the genome correlates with multicellularity; however, we found that unicellular ciliates Tetrahymena thermophila (Tt) and Paramecium(More)
We developed a modified immunofluorescence protocol that permitted visualization of microtubules inside the macronucleus of the ciliate Tetrahymena. Although the amitotically dividing macronucleus lacks a spindle, an elaborate system of microtubules is assembled inside the macronucleus and between the macronucleus and the cortex. Microtubules could not be(More)
In the molecular mechanism of division plane determination and contractile ring formation, Tetrahymena 85kDa protein (p85) is localized to the presumptive division plane before the formation of the contractile ring. p85 directly interacts with Tetrahymena calmodulin (CaM) in a Ca2+-dependent manner, and p85 and CaM colocalize in the division furrow. A(More)
Using an F-actin affinity column, a 60 kDa fragment of a 71 kDa F-actin-binding protein was partially purified from Tetrahymena pyriformis. After digestion of the 60 kDa fragment with cyanogen bromide, the N-terminal 21-amino acid sequence of one of the resulting peptides was found to show sequence similarity to a region near the actin-binding site (amino(More)
Uniparental disomy (UPD) is defined as the presence of a chromosome pair that derives from only one parent in a diploid individual. The human TRKA gene on chromosome 1q21-q22 encodes a receptor tyrosine kinase for nerve growth factor and is responsible for an autosomal recessive genetic disorder: congenital insensitivity to pain with anhidrosis (CIPA). We(More)
Though actin is ubiquitous in eukaryotes, its existence has not been clearly proven in Tetrahymena. Recently, we have succeeded in cloning and sequencing the Tetrahymena actin gene using a Dictyostelium actin probe (Hirono, M. et al. (1987) J. Mol. Biol. 194, 181-192). The primary structure of the Tetrahymena actin deduced from the nucleotide sequence of(More)