Multiple actin-related proteins of Saccharomyces cerevisiae are present in the nucleus.
An increasing number of actin-related proteins (Arps), which share the basal structure with skeletal actin but possess distinct functions, have been found in a wide variety of organisms. Individual Arps of Saccharomyces cerevisiae were classified into Arps 1-10 based on the relatedness of their sequences and functions, where Arp1 is the most similar to actin, and Arp10 is the least similar. While Arps 1-3 and their orthologs in other organisms are localized exclusively in the cytoplasm, Arp4 (also known as Act3) is localized in the nucleus and is involved in transcriptional regulation. Here we examined the more divergent Arps for possible nuclear functions. We show that Arps 5-9 are localized in the nucleus, but Arp10 is not. The nuclear export signals identified in actin are well conserved in the cytoplasmic Arps, Arps 1-3, but less conserved in the nuclear Arps. Gel filtration chromatography experiments show that the nuclear Arps are larger than monomer in size and thus are present in multi-protein complexes. Since nuclear protein complexes containing Arps are found to be responsible for histone acetylation and chromatin remodeling, it is suggested that most of the divergent Arps are involved in the !transcriptional regulation through chromatin modulation.
Harata
M
M
Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Division of Life Science, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 981-8555, Japan. mharata@biochem.tohoku.ac.jp
Oma
Y
Y
Tabuchi
T
T
Zhang
Y
Y
Stillman
D J
DJ
Mizuno
S
S
D000199:Actins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000737:chemistry*; D002843:Chromatin / Q000378:metabolism; D002850:Chromatography, Gel; D003593:Cytoplasm / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D046911:Macromolecular Substances; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013347:Subcellular Fractions / Q000737:chemistry
D000199:Actins; D002843:Chromatin; D005656:Fungal Proteins; D008164:Luminescent Proteins; D046911:Macromolecular Substances; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins