Carbohydrate–carbohydrate interaction provides adhesion force and specificity for cellular recognition

Abstract

The adhesion force and specificity in the first experimental evidence for cell–cell recognition in the animal kingdom were assigned to marine sponge cell surface proteoglycans. However, the question whether the specificity resided in a protein or carbohydrate moiety could not yet be resolved. Here, the strength and species specificity of cell–cell recognition could be assigned to a direct carbohydrate–carbohydrate interaction. Atomic force microscopy measurements revealed equally strong adhesion forces between glycan molecules (190–310 piconewtons) as between proteins in antibody–antigen interactions (244 piconewtons). Quantitative measurements of adhesion forces between glycans from identical species versus glycans from different species confirmed the species specificity of the interaction. Glycan-coated beads aggregated according to their species of origin, i.e., the same way as live sponge cells did. Live cells also demonstrated species selective binding to glycans coated on surfaces. These findings confirm for the first time the existence of relatively strong and species-specific recognition between surface glycans, a process that may have significant implications in cellular recognition.

Glycosylation Alters Dimerization Properties of a Cell-surface Signaling Protein, Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 (CEACAM1)

“…Asn-81 is sufficiently close to the dimer interface for the termini of an attached complex glycan to reach a positively charged patch composed of four arginines and two lysines, Lys-35, Arg-38, and Arg-43 that runs across the base of the dimer. Glycanglycan interactions are also known to occur, particularly in sialic acid-terminated glycans in which bridging by divalent cations can be important (50). If such interactions exist, variation in glycosylation could be an important modulator of signaling the cis and trans homotypic interactions that appear to affect cellular function.…”

Carbohydrate-Carbohydrate Interactions Mediated by Sulfate Esters and Calcium Provide the Cell Adhesion Required for the Emergence of Early Metazoans

“…13 and 16 -20). Studies using single-molecule force spectroscopy have shown that the average self-interaction forces of sulfated polysaccharides from AFs in the presence of calcium lies between 190 and 310 piconewtons, depending on the species studied (13). The binding forces between homologous sulfated polysaccharides from AFs are significantly stronger than between those from different species, confirming the specificity of those interactions (13).…”

“…The structures of AFs resemble those of aggrecans: large, extracellular membrane-bound, aggregating, and modular proteoglycans (15). In the marine sponge Microciona prolifera the AF is constructed by a protein core attached to two different carbohydrate units: a small 6-kDa glycan that mediates the interaction of the AF with putative receptors present in the cell membrane and a larger 200-kDa sulfated polysaccharide, which binds homophilically with identical units on the AFs of adjacent cells (13)(14)(15)(16).…”

“…Carbohydrate selfadhesion is maintained by relatively weak forces that can increase in orders of magnitude upon the multimerization of individual epitopes into polysaccharides (10). Some examples of specific carbohydrate self-interactions include the multivalent binding of Lewis x epitopes involved in the first steps of embryogenesis (11), glycolipid-glycolipid interactions controlling cell adhesion, spreading, and motility (12), and self-interactions of sulfated polysaccharides leading to species-specific cell adhesion in sponges (13).…”

“…H TOCSY spectra were run as previously described (30,31) with 4046 ϫ 400 points with a spin-lock field of 10 kHz and a mix time of 80 ms. 13 C, 1 H HSQC spectra were run with 1024 ϫ 256 points and globally optimized alternating phase rectangular pulses for decoupling. 13 C, 1 H HMBC spectrum was recorded with 1024 ϫ 256 points, with a 60-ms delay for evolution of long-range couplings and was set with no decoupling during acquisition time. Chemical shifts are displayed relative to external trimethylsilylpropionic acid at 0 ppm for 1 H and relative to methanol for 13 C. Chemical Modifications of DaSP-Native DaSP (50 mg) was submitted to desulfation or carboxyl-reduction reactions.…”