High impact information on ARP1

• We have identified in S. cerevisiae a novel actin-related gene, ACT5, in the Arp1 family [1].
• The phenotype of a double mutant lacking dynein and Act5p is similar to that of single mutants [1].
• The requirement of the ACT2 gene for vegetative growth of yeast cells and the existence of related genes in other eukaryotes indicate an important and conserved role for these actin-like proteins [2].
• New yeast actin-like gene required late in the cell cycle [2].
• Rat spleen DNA digested by the EcoRI restriction enzyme contains at least 12 different fragments with actin-like sequences but only one which hybridized, in very stringent conditions, with the skeletal muscle cloned cDNA probe [3].

Biological context of ARP1

• The arp1 bni1 mutant showed a synthetic lethal phenotype while the cin8 bni1 mutant did not, suggesting that Bni1p functions in a kinesin pathway but not in the dynein pathway [4].
• ACT3, which we recently discovered, is an essential gene coding for a polypeptide of 489 amino acids (Act3p), with a calculated molecular mass of 54.8 kDa [5].
• Molecular genetic analysis indicates ACT3 is represented by a single gene from which the corresponding mRNA is expressed at a low level compared to ACT1 [6].
• The sequence of a genomic clone indicates ACT3 lies adjacent to and is transcribed convergently with respect to FUR1 on chromosome VIII [6].
• Like strains lacking the cytoplasmic dynein heavy chain Dyn1p or the centractin homologue Act5p, nip100Delta strains are viable but undergo a significant number of failed mitoses in which the mitotic spindle does not properly partition into the daughter cell [7].

Anatomical context of ARP1

• Molecular dissection of ARP1 regions required for nuclear migration and cell wall integrity checkpoint functions in Saccharomyces cerevisiae [8].
• We investigated the mechanism of these movements in living cells using video analysis of GFP-labeled microtubules in wild-type cells and in EB1 and Arp1 mutants, which are defective in the first and second steps, respectively [9].
• In an attempt to identify the messenger ribonucleic acid coding for the actin-like protein, yeast polyadenylic acid-rich ribonucleic acid was translated in wheat germ and reticulocyte cell-free protein-synthesizing systems [10].

Associations of ARP1 with chemical compounds

• The yeast actin-like protein yielded a single spot on two-dimensional polyacrylamide gel electrophoresis, suggesting that a single protein species was present [10].

Other interactions of ARP1

• Unlike the actin mutations, none of the ARP1 alleles disrupt filament formation; however, one pointed-end allele delayed the elution of Arp1p on gel filtration, consistent with loss of additional subunits [11].
• Moreover, genetic depletion experiments indicate that the binding of Nip100p to Act5p is dependent on the presence of Jnm1p [7].
• Dynein localization required Pac1 and, like Pac1, was enhanced in cells lacking the dynactin component Arp1 or the cortical attachment molecule Num1 [12].
• Bim1p appears to regulate the timing of cytokinesis as demonstrated by a genetic interaction with Act5, a component of the yeast dynactin complex [5] [13].

Analytical, diagnostic and therapeutic context of ARP1

• Expression of Arp1 mRNA in P. carinii was detectable via synthesis of cDNA and subsequent PCR amplification [14].

References