Disease relevance of actin

• While introns in the 5' untranslated region and between codons 41-42 and 121-122 are present in many organisms, the introns in positions 168 and 246-247 had only been found previously in actin genes from the nematode Onchocerca volvulus and the green alga Volvox carterii, respectively [1].

High impact information on actin

• Other alleles alter the site at which myosin binds actin [2].
• In DOCK2-/- lymphocytes, chemokine-induced Rac activation and actin polymerization were almost totally abolished [3].
• In hair cells of the inner ear, evidence suggests that an extracellular tip link pulls on a channel, which attached intracellularly to actin via a tension-regulating myosin 1beta [4].
• This latter phenotype could be precisely correlated with a previously unknown actin barbed-end-capping activity, which is present in the C terminus of the EPS-8A isoform [5].
• A novel actin barbed-end-capping activity in EPS-8 regulates apical morphogenesis in intestinal cells of Caenorhabditis elegans [5].

Biological context of actin

• Recent insights from this system have determined the involvement in morphogenesis of key proteins, including the actin-regulating WASP and Ena proteins, potential guidance molecules such as the Eph and Robo receptors, and the cell-cell signaling proteins of the Wnt pathway [6].
• RNA interference of Ce-kettin caused weak disorganization of the actin filaments in body wall muscle [7].
• Although the model refers primarily to the locomotion of nematode sperm, it has important implications for the mechanics of actin-based cell motility [8].
• Both of the amino acid sequences resemble vertebrate cytoplasmic actin more than vertebrate muscle actin [9].
• For both revertants, reversion was accompanied by an actin gene rearrangement [10].

Anatomical context of actin

• Given these advantages, it has been possible to use C. elegans to investigate the different ways in which the actin cytoskeleton drives the cellular rearrangements underlying morphogenesis, through regulated polymerization or actomyosin contraction [6].
• ERM proteins regulate cell morphology and plasma membrane dynamics by reversibly anchoring actin filaments to integral plasma membrane proteins [11].
• TM4SF10 colocalized with ZO1 and p120ctn in undifferentiated confluent podocytes and also colocalized with the tips of actin filaments at cell contacts [12].
• Tropomyosin shows a distinct pattern in spermatids, but is located in the MSP and actin-containing cap in spermatozoa [13].
• It is hypothesized that actin plays a role in the shaping of the cell and in the arrangement of its organelles during nematode spermiogenesis, when MSP is present, in an inactive state, in the fibrous bodies [13].

Associations of actin with chemical compounds

• Actin proteins in the parasitic nematode Haemonchus contortus were partially purified by a new method based on precipitation with podophyllotoxin and dimethylsulfoxide [14].

Physical interactions of actin

• Some of the residues considered essential for actin and calcium binding in gelsolin S1 and villin V1 are also well conserved [15].
• Actin filaments in the body wall muscle of the nematode Caenorhabditis elegans are attached to the sarcolemma through vinculin-containing structures called dense bodies, Z-line analogues [16].

Other interactions of actin

• Sperm of the nematode, Ascaris suum, are amoeboid cells that do not require actin or myosin to crawl over solid substrata [17].
• Moreover, nematode sperm lack detectable molecular motors or the battery of actin-binding proteins that characterize actin-based motility [8].
• The very thin filaments were visualized in gelsolin-treated actin filament-free fibres [18].
• The increased synthesis of forms of myosin, actin and troponin in the nematode living in the rapid-responder SWR host may relate to the attempted reorganisation or repair of the cytoskeleton and/or muscle layer in the host immune initiated, increased mucus production and smooth muscle activity within intestinal environment [19].
• These results suggest that muscle contraction has only minor influence on the tropomyosin's protective role against ADF/cofilin and AIP1, and that the two functions of tropomyosin in actin stability and muscle contraction are independent of each other [20].

Analytical, diagnostic and therapeutic context of actin

• Actin from the nematode, Caenorhabditis elegans, is a single electrofocusing species [21].
• Immunofluorescence microscopy revealed that PKC3 accumulates near cortical actin cytoskeleton/plasma membrane at the apical surface of intestinal cells and in embryonic cells [22].
• Here, we performed a detailed characterization of the pha-2 phenotype using cell-type-specific reporters, physical manipulation of the nuclei in pharyngeal muscle cells using "optical tweezers", electron microscopy, staining of the actin cytoskeleton as well as phenotypic rescue and ectopic expression experiments [23].
• It seems to show actin, UNC-87 and Proteasome regulatory particle may play distinct roles in specific aspects of organization of macromolecular structures under desiccation stress [24].

References