Disease relevance of Act87E

• Here, wild-type (WT) human alpha-cardiac actin and a mutant E99K actin have been expressed and purified from the baculovirus/insect cell expression system [1].
• Mutations in Myosin ID completely reverse the left-right axis (situs inversus), a phenotype that is dependent on an intact actin cytoskeleton [2].
• Here, we show that tau-induced neurodegeneration is associated with accumulation of filamentous actin (F-actin) and the formation of actin-rich rods in Drosophila and mouse models of tauopathy [3].
• Epstein-Barr virus infection induces expression in B lymphocytes of a novel gene encoding an evolutionarily conserved 55-kilodalton actin-bundling protein [4].
• Stage-specific expression of two actin genes in the yellow fever mosquito, Aedes aegypti [5].

Psychiatry related information on Act87E

• These findings raise the possibility that a direct interaction between tau and actin may be a critical mediator of tau-induced neurotoxicity in Alzheimer's disease and related disorders [3].

High impact information on Act87E

• However, DmIKK epsilon-mediated degradation of DIAP1 does not regulate apoptosis as might be predicted but instead regulates actin dynamics, cell morphology, and the differentiation of sensory organ precursor cells [6].
• These composite data define three main patterns of actin gene expression which are correlated with changing Drosophila morphology, particularly muscle differentiation and reorganization [7].
• Furthermore, the messages encoding alpha-tubulin, beta-tubulin, and actin are found associated with one-third to one-half as many total ribosomes in heat-shocked cells as in cells incubated at 25 degrees C. Increased temperature should lead to increased output of protein per ribosome [8].
• Each of the approximately 30,000 wing epithelial cells constructs an actin-rich prehair that protrudes from its distal vertex and points distally [9].
• These include proteins that participate in haemocyte development, vesicle transport, actin cytoskeleton regulation and a cell surface receptor [10].

Biological context of Act87E

• The Act87E transcription unit is 1.57 kb and includes a 556-base intervening sequence in the 5' leader of the gene [11].
• By in situ hybridization with a series of deficiencies that break in 87E, Act87E was localized to a region encompassing one to three faint, polytene chromosome bands [11].
• The lower density of negative charge in subdomain 1 of actin therefore weakens the actomyosin interaction sufficiently to decrease the force and motion generating capacity of E99K actin, thus providing the primary insult that ultimately leads to the disease phenotype [1].
• Here we have addressed how two actin regulators, capping protein, a barbed end binding protein, and the Arp2/3 complex, a potent actin assembly nucleator, function to generate properly organized bundles [12].
• The implications of the failure to identify recessive lethal mutations in the actin gene are discussed in reference to studies of other conserved multigene families and other muscle protein mutations [11].

Anatomical context of Act87E

• Drosophila melanogaster bristle development is dependent on actin assembly, and prominent actin bundles form against the elongating cell membrane, giving the adult bristle its characteristic grooved pattern [12].
• In salivary glands and follicle cells the head and neck domains were concentrated in the cell nucleus, where the minus end of each actin filament is located [13].
• An intron at codon 150 is common to a plant actin gene and the skeletal muscle acting gene [14].
• If, however, Drosophila mRNA was translated in a mRNA-dependent rabbit reticulocyte lysate system, an additional 43-kDa actin intermediate was observed [15].
• Myosin VI stabilizes an actin network during Drosophila spermatid individualization [16].

Associations of Act87E with chemical compounds

• These data confirm that N-acetyl-cysteine at the N terminus affects actomyosin interactions, probably by reducing formation of the initial actomyosin collision complex, a process known to involve the actin N terminus [17].
• Our results show that ACT88F is N-terminally processed in vivo as a class II actin by removal of the first two amino acid residues (Met and Cys), but that uniquely the N terminus is not acetylated [17].
• The cDNA encoding the entire RVGP gene was cloned in an expression plasmid under the control of the constitutive actin promoter (Ac), which was co-transfected into S2 cells together with a hygromycin selection plasmid [18].
• Intron positions typical of other known plant actin genes are conserved in these clones [19].
• The removal of Ac-Cys from Drosophila actin is thus similar to removal of Ac-Met from the NH2 terminus of class I actins although in the case of the class II actins, it is the second amino acid that is removed as an acetylated species [15].

Physical interactions of Act87E

• We interpret these results as possibly caused either by effects on A1 myosin light chain binding or conformational changes within the subdomain 1 of actin, which contains the myosin binding site [20].
• Biochemical studies showed that both ninaC proteins bind actin filaments and cosediment with actin filaments in an ATP-sensitive manner [21].

Enzymatic interactions of Act87E

• Previous studies with Drosophila actin showed that the first detectable intermediate is one with an Ac-Cys NH2 terminus which is subsequently cleaved in a novel reaction to expose the Asp [22].

Other interactions of Act87E

• Actomyosin kinetics and in vitro motility of wild-type Drosophila actin and the effects of two mutations in the Act88F gene [20].
• In a time- and acetyl-CoA-dependent fashion, Met-Cys-Asp-actin was processed to the mature actin, presumably through an Ac-Met-Cys-Asp intermediate [22].
• These results outline structural roles for the ninaC proteins, and are consistent with the notion, suggested by their amino acid sequences, that the proteins are actin-based mechanoenzymes [21].
• Germ-line armadillo mutations appear to disrupt processes requiring cell adhesion and integrity of the actin cytoskeleton, consistent with a role for Armadillo in cell-cell adhesive junctions [23].
• In nurse cells that contain excess quail but no fascin, the cytoplasmic actin network initially appears wild type but then becomes disorganized in the final stages of nurse cell cytoplasm transport [24].

Analytical, diagnostic and therapeutic context of Act87E

• Sequence analysis of the indirect flight muscle actin-encoding gene of Drosophila simulans [25].
• Purification entails lysis in a low salt, sucrose buffer that contains ATP, chromatography on DEAE-cellulose, precipitation with actin in the absence of ATP, gel filtration in a discontinuous KI-KCl buffer system, and hydroxylapatite chromatography [26].
• Similarly, in Drosophila, actin and myosin 2 localization and cell constriction at the margin of the epidermis mediate dorsal closure and are controlled by Misshapen [27].
• Actin-myosin structures align across multiple cells during rosette formation, and adherens junction proteins assemble in a stepwise fashion during rosette resolution [28].
• With the use of a pulse-chase protocol and two-dimensional gel electrophoresis, it has been found that actin III is synthesized as a precursor of the more stable cytoplasmic actin II [29].

References