Arylsulfatase exists as non-enzymatic cell surface protein in sea urchin embryos

Abstract

The physiological role of arylsulfatase (Ars) and its function during development have yet to be satisfactorily defined in any species, though the proteins are widely distributed and the genes have been cloned from various organisms. Here we report the dual location of two types of Ars in sea urchin embryos. The majority of sea urchin Ars does not exhibit enzyme activity and is extracellularly distributed in aboral ectoderm cells (nonenzymatic Ars). Only a small portion has enzyme activity and is localized in lysosomal vesicles (enzymatic Ars). The elution pattern of Ars proteins processed by DEAE‐cellulose or analytical gel‐column chromatography reveals that although the molecular radius of enzymatic Ars differs from that of nonenzymatic Ars, they have the same charge. Furthermore, sedimentation analysis shows that purified Ars of sea urchin embryos is soluble in the absence of divalent cations but becomes insoluble in the presence of Ca2+ or Mg2+. Taken together, the present results suggest that nonenzymatic Ars is a new member of the cell surface component or extracellular matrix. It is possible that this cell surface Ars plays an important role in morphogenesis of sea urchin embryos. J. Exp. Zool. 280:220–230, 1998. © 1998 Wiley‐Liss, Inc.

Sea urchin arylsulfatase, an extracellular matrix component, is involved in gastrulation during embryogenesis

“…Embryos were fixed in 100% methanol at −20°C for 20 min and stained with affinity purified polyclonal antibodies against HpArs (Mitsunaga-Nakatsubo et al 1998). The primary antibodies were detected with Oregon greenconjugated goat anti-rabbit secondary antibodies (Molecular Probes Europe BV, the Netherlands).…”

“…The aliquot of each fraction was subjected to electrophoresis and the protein was blotted to polyvinylidene fluoride (PVDF) membranes (Immobilon Transfer Membranes; Millipore). The HpArs protein was detected with affinity purified anti-HpArs antibodies (Mitsunaga-Nakatsubo et al 1998), followed by anti-rabbit IgG antibodies conjugated to horseradish peroxidase (PIERCE). The chemiluminescence of Super Signal West Dura Extended Duration Substrate (PIERCE) by hydrolysis with horseradish peroxidase was detected by X-ray film.…”

“…Using the sea urchin embryo, we previously demonstrated that the bulk of Hemicentrotus pulcherrimus Ars (HpArs) does not exhibit enzyme activity and is located on the apical surface of the epithelial cells (Akasaka et al 1990;Mitsunaga-Nakatsubo et al 1998). A signal peptide destined for extracellular space is located in the amino terminal of the HpArs protein.…”

“…During sea urchin development, the expression of Ars begins just before the onset of dynamic morphogenetic movement of the epithelial cells (Rapraeger and Epel 1981;Sasaki et al 1988) and the amount of HpArs protein constitutes more than 0.5% of total protein in the embryo after the gastrula stage (Sasaki et al 1987). The HpArs protein co-localizes with the sulfated polysaccharide which accumulates mainly on the apical surface of epithelial cells (Mitsunaga-Nakatsubo et al 1998;Akasaka and Terayama 1983). We also demonstrated that the HpArs proteins extracted from the sea urchin embryos are insolubilized in the presence of Ca 2+ (Mitsunaga-Nakatsubo et al 1998).…”

“…The HpArs protein co-localizes with the sulfated polysaccharide which accumulates mainly on the apical surface of epithelial cells (Mitsunaga-Nakatsubo et al 1998;Akasaka and Terayama 1983). We also demonstrated that the HpArs proteins extracted from the sea urchin embryos are insolubilized in the presence of Ca 2+ (Mitsunaga-Nakatsubo et al 1998). It has been reported that expansion of the prospective ectoderm cells as a sheet toward the vegetal pole, employing tractoring on components of the apical extracellular matrix, contribute to the primary invagination during gastrulation (Burke et al 1991, Davidson et al 1995, 1999Takata 2000, 2004;Takata and Kominami 2001).…”