Biomedical subjects

S Sofuku

Publications and source records attributed to S Sofuku.

10 recordsLinked to original sources

PubMed2001

An RGDS peptide-binding receptor, FR-1R, localizes to the basal side of the ectoderm and to primary mesenchyme cells in sand dollar embryos.

Immunoblotting using polyclonal antibodies (pAb) raised against an FR-1 receptor (FR-1R), a 57 kDa Arg-Gly-Asp-Ser (RGDS)-binding protein, of the sand dollar Clypeaster japonicus showed that the pAb monospecifically bound to the protein. FR-1R was present in purified plasma membrane, suggesting that the protein is a membrane-bound protein. The molecular structure of FR-1R did not change throughout the early embryogenesis, whereas its expression changed significantly during this period. FR-1R was present in the cortex of unfertilized eggs and was then transferred to the hyaline layer soon after the fertilization. The hyaline layer retained FR-1R immunoreactivity during early embryogenesis. FR-1R appeared on the basal side of the ectoderm at the morula stage and was retained basolaterally, at least, to the early gastrula stage. In mesenchyme blastulae, FR-1R was also present on the surface of primary mesenchyme cells (PMC). FR-1R was localized on the basal side of the ectoderm in early gastrulae, exclusively at the place where PMC formed ventrolateral aggregates, and at the apical tuft ectoderm. In vitro, PMC bound to FR-1R and its binding was inhibited in the presence of a synthetic RGDS peptide or the pAb. The pAb introduced into the blastocoele perturbed PMC migration and gastrulation. FR-1R was weakly recognized by antihuman integrin beta5 subunit pAb.

Animals↗

PubMed1999

Synthesis of cyclic oligopeptides containing an Arg-Gly-Asp (RGD) sequence.

The synthesis of cyclic RGD peptides with 8-10 residues cyclized by an amide bond and the relationship between their structure and activity (i.e. circular dichroism spectrum and inhibition of platelet aggregation) are reported. The linear peptides were synthesized by the solution method and their cyclization was performed in high dilution using DPPA.

Azides↗

PubMed1997

Histological distribution of FR-1, a cyclic RGDS-peptide, binding sites during early embryogenesis, and isolation and initial characterization of FR-1 receptor in the sand dollar embryo.

A fibronectin-related synthetic cyclic H-Cys-Arg-Gly-Asp-Ser-Pro-Ala-Ser-Ser-Cys-OH (RGDSPASS) peptide (FR-1) binding site in the embryo of the sand dollar Clypeaster japonicus was specified using dansyl-labeled FR-1 (Dns-FR-1) and horseradish peroxidase-labeled FR-1, and an FR-1 receptor was isolated using FR-1-affinity column chromatography. The FR-1 introduced to the blastocoel of blastulae inhibited primary mesenchyme cell (PMC) migration in mesenchyme blastulae, and complete gastrulation and spicule differentiation in gastrulae. The Dns-FR-1 bound to the entire basal side of the ectoderm in mesenchyme blastulae, and then restricted to the basal side of the ectoderm at the apical tuft region and the vegetal hemisphere in early gastrulae. The cytoplasm of the archenteron also bound to Dns-FR-1. In PMC, Dns-FR-1 bound to the nucleus and cytoplasmic reticular features. In unfertilized eggs, Dns-FR-1 bound to the entire cytoplasm, particularly to the oval-shaped granules and the nuclear envelope, but only to the cytoplasm after fertilization. Relative molecular mass (Mr) of the FR-1-binding protein was 240 kDa under non-reducing conditions and 57 kDa under reducing conditions. The FR-1 receptor protein bound anti-sea urchin integrin (Spl) betaL subunit antibodies raised against the embryos of Strongylocentrotus purpuratus. Immunohistochemistry showed that the antibody binding site was similar to the histochemical distribution of Dns-FR-1. However, Mr of the FR-1 receptor is distinctively larger than that of the Spl betaL subunit.

Animals↗

PubMed1992

Sialogogic effects on rat submandibular gland of analogs of the C-terminal hexapeptide of substance P.

The sialogogic response of submandibular glands to analogs of the C-terminal hexapeptide of substance P with various amino acids at the N-terminus was investigated in urethane-anesthetized rats. The rank order of potencies was as follows: SP greater than (pGlu6)SP6-11 much greater than (Dab6)SP6-11 greater than (Orn6)SP6-11 greater than (Gln6)SP6-11 greater than (Lys6)SP6-11 much greater than (Ala6)SP6-11. These results suggest that the sialogogic activity of the analogs of the C-terminal hexapeptide is influenced by the steric effects of the N-terminal amino acid, and the nature of its side chain is of particular importance.

Animals↗

PubMed1990

A fibronectin-related synthetic peptide, Pro-Ala-Ser-Ser, inhibits fibronectin binding to the cell surface, fibronectin-promoted cell migration in vitro, and cell migration in vivo.

The biological activity of the amino acid sequence consisting of the immediate carboxyl terminus side of the Arg-Gly-Asp-Ser (RGDS) amino acid sequence in the cell-binding domain of intact fibronectin (FN) molecules was examined using synthetic peptides [RGDS, Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP), Arg-Gly-Asp-Ser-Pro-Ala-Ser-Ser-Lys-Pro (RGDSPASSKP), Pro-Ala (PA), Pro-Ala-Ser (PAS), Pro-Ala-Ser-Ser (PASS), and Pro-Ala-Ser-Ser-Lys (PASSK)]. These peptides were applied to the primary mesenchyme cells (PMCs) of the sea urchin, Clypeaster japonicus. In vitro immunohistochemistry indicated that the binding of exogenous FN to the PMC surface was inhibited by the peptides RGDSPASSKP and PASS, but not by RGDS, GRGDSP, PA, or PAS. PASS and RGDS introduced into the blastocoel also inhibited PMC migration in vivo. FN-promoted PMC migration in vitro was also inhibited by PASS and RGDS. The present results indicate that the PASS peptide inhibits FN binding to the PMC surface and promotes PMC migration, suggesting that the FN molecule uses the PASS amino acid sequence to bind to the PMC surface and to promote PMC migration in the blastocoel.

Amino Acid Sequence↗

PubMed1984