Assembly of the sea urchin fertilization membrane: isolation of proteoliaisin, a calcium-dependent ovoperoxidase binding protein.

Abstract

Fertilization of the sea urchin egg is accompanied by the assembly of an extracellular glycoprotein coat, the fertilization membrane. Assembly of the fertilization membrane involves exocytosis of egg cortical granules, divalent cation-mediated association of exudate proteins with the egg glycocalyx (the vitelline layer), and cross-linking of the assembled structure by ovoperoxidase, a fertilization membrane component derived from the cortical granules. We have identified and isolated a new protein, which we call proteoliaisin, that appears to be responsible for inserting ovoperoxidase into the fertilization membrane. Proteoliaisin is a 250,000-Mr protein that binds ovoperoxidase in a Ca2+-dependent manner, with half-maximal binding at 50 ~M Ca 2+. Other divalent cations are less effective (Ba 2+, Mn 2÷, and Sr 2÷) or ineffective (Mg 2~ and Cd 2÷) in mediating the binding interaction. Binding is optimal over the physiological pH range of fertilization membrane assembly (pH 5.5-7.5). Both proteoliaisin and ovoperoxidase are found in isolated, uncross-linked fertilization membranes. We have identified several macromolecular aggregates that are released from uncross-linked fertilization membranes after dilution into divalent cation-free buffer. One of these is an ovoperoxidase-proteoliaisin complex that is further disrupted only upon the addition of EGTA. These results suggest that a Ca2÷-stabilized complex of ovoperoxidase and proteoliaisin forms one structural subunit of the fertilization membrane.

Rendezvin: An Essential Gene Encoding Independent, Differentially Secreted Egg Proteins That Organize the Fertilization Envelope Proteome after Self-Association

“…For example, the association of proteoliaisin with the VL-component RDZ 120 [anti-] is in agreement with previous experiments showing purified, endogenous proteoliaisin binds to the egg VL (Weidman et al, 1985). Also, RDZ 90 [anti-␦] preferentially asso- ciates with a 60-kDa protein, presumed to be RDZ 60 [anti-␣], in an interaction that is reminiscent of a 69-Å Stokes radius complex shown to consist of a 108-and 59-kDa protein .…”

“…The first apparent effect of this union [between sperm and egg] After 150 yr, the major structural proteins of this "circular line" and how they assemble to form an "envelope" have now been identified (Weidman et al, 1985;Wessel, 1995;Wessel et al, 2000;. Here, we document the final components of this FE, which originate from rdz.…”

Developmental Expression of Echinonectin, an Endogenous Lectin of the Sea Urchin Embryo

“…At least seven types of vesicles have been identified in the egg, some of which may ultimately prove to be related or identical to one another. These include: 1) yolk vesicles; 2) cortical granules, which contain several proteins including hyalin, egg protease, /3-glucanase, ovoperoxidase and proteoliasin (5,10,18,38,40); 3) pigment granules (30); 4) "apical lamina vesicles", which contain proteins recognized by MAb 8 d l l (4) and probably also the fibropellins, two glycoproteins of the apical lamina (7); 5) "basal lamina vesicles", which contain proteins that crossreact with antibodies against several vertebrate extracellular matrix components as well as other unidentified antigens that are later incorporated into both the hyaline layer and the basal lamina (39); 6) ENcontaining vesicles; and; 7) acidic vesicles that can be distinguished by fluorescent staining with pHsensitive basic dyes such as acridine orange (9,20). Acidic vesicles may prove to be identical to other classes of vesicle (e.g., basal lamina or apical lamina vesicles) that have been defined by other markers.…”

Extracellular matrix modifications at fertilization: regulation of dityrosine crosslinking by transamidation

“…(2) Transamidation may tether specific proteins to the fertilization envelope. Ovoperoxidase glutamines, for example, could be covalently bound to proteoliaisin lysines, thereby establishing more permanent association between these two proteins (Somers et al, 1989;Weidman et al, 1985); it is still possible to resolve the two proteins after pharmacological inhibition of ovoperoxidase (Deits et al, 1984;Showman and Foerder, 1979) because transamidation is repressed in the intercast region, where the majority of these proteins reside in the expanded fertilization envelope (Mozingo et al, 1994). Alternatively, (3) crosslinking of intra-enzyme glutamine and lysine residues may positively regulate ovoperoxidase, perhaps locking it in an active state following hysteretic modification (Deits and Shapiro, 1985;Deits and Shapiro, 1986).…”

“…Development 136 (11) also be permanently tethered to proteoliaisin by transamidation, limiting its redistribution to other domains of the fertilization envelope (Mozingo et al, 1994;Weidman et al, 1985). (6) Soluble CGSP1 and active transglutaminases released from the zygote surface and/or not retained in the fertilization envelope both diffuse away from the zygote, while the permeability of the fertilization envelope remains unrestricted.…”