Tropomyosin isoforms present in the sea anemone, Anthopleura japonica (Anthozoa, Cnidaria)

Abstract

Five isoforms of tropomyosin, designated as TMa, TMb, TMc, TMd, and TMe, were detected in the sea anemone, Anthopleura japonica. The apparent molecular weights of these isoforms were estimated to be approximately 30 kD to 37.5 kD, and their pI values were approximately 4.55 (TMa and TMb) and 4.65 (TMc, TMd, and TMe). Although sea anemone tropomyosin isoforms have the ability to bind to rabbit skeletal muscle actin, they preferably bind to actin at higher concentrations of Mg(2+) (10-20 mM) and slightly lower pH (6.2-7.2) than those used in conventional conditions. Antigenic properties of sea anemone tropomyosin seemed to be considerably specific to each isoform. Distribution of tropomyosin isoforms in the sea anemone body was somewhat portion-specific. TMa, TMb, and TMe were detected similarly in the extracts from tentacle, oral disc, column, mouth, and pedal disc. Although TMc and TMd were detected abundantly in the tentacle extract and moderately in the column and mouth extracts, these components were not contained in the pedal disc extract and detected only faintly in the oral disc extract.

Serotonergic signals enhanced hamster sperm hyperactivation

“…Sperm proteins were extracted using the following method. In brief, sperm obtained from the epididymis were washed once with 0.9% (w/v) NaCl and collected by centrifugation at 4°C for 10 min at 15,000 × g. Sperm pellets were suspended at 100 mg/ml (w/v) in sodium dodecyl sulfate (SDS) buffer containing 5 M urea, 0.1% SDS, 1% 2-mercaptoethanol, and 75 mM Tris-HCl (pH 6.8) [27]. After pipetting, the suspension was incubated on ice for 10 min.…”

Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration

“…Myosin Essential and Regulatory Light Chains, Myosin Light Chain-Kinase and Phosphatase, as well as the smooth muscle ATPase regulator Calponin are present in cnidarians genomes (Steinmetz et al, 2012) but have not been functionally characterized yet. Several Tropomyosin paralogs have also been described in cnidarians (Baader et al, 1993; López de Haro et al, 1994; Gröger et al, 1999, 2000; Fujinoki et al, 2002; Steinmetz et al, 2012), including one specific to the striated muscle cells of Podocoryna (Gröger et al, 1999, 2000). However, Troponins, important components of the striated muscle thin filaments, have to date not been found in any cnidarian genomes (Steinmetz et al, 2012).…”

Tissue specificity of tropomyosin isoform in the mussel, Mytilus galloprovincialis

“…The mussel, M. galloprovincialis was purchased from a fish market and tropomyosin extracts were prepared as described previously 14,18) . Samples of the anterior pedal retractor muscle, translucent and opaque portions of adductor muscle, cardiac muscle, gills and mantle were suspended in 50 volumes of acetone, minced with scissors, washed seven times with acetone, air dried, and used as acetone powder, which was treated with 100 volumes of 5% (w/v) trichloroacetic acid (TCA) for 1 hour at room temperature to prevent endogenous proteolysis 19) .…”

“…Generally, there are multiple tropomyosin isoforms that expressed by multiple genes and by alternative splicing of transcripts of those genes in many animals [2][3][4][5][6][7][8][9] . Moreover, the isoforms show a tissue-specific distribution in many animals; for example, human 10) , chicken 11) , salmonid fish 12) , lobster 13) , bivalve [14][15][16] , sea urchin 17) , and sea anemone 18) . Although it is likely that tissue-specific distribution is associated with the roles of the isoforms in the tissues, the functions of tropomyosin itself in the absence of troponin are not well known.…”