Self-recognition and Ca2+-dependent carbohydrate–carbohydrate cell adhesion provide clues to the Cambrian explosion
Burger, Max M.
MetadataShow full item record
The Cambrian explosion of life was a relatively short period ca. 540 million years ago that marked a generalized acceleration in the evolution of most animal phyla, but the trigger of this key biological event remains elusive. Sponges are the oldest extant Precambrian metazoan phylum and thus a valid model to study factors that could have unleashed the rise of multicellular animals. One such factor is the advent of self/non-self recognition systems, which would be evolutionarily beneficial to organisms to prevent germ cell parasitism or the introduction of deleterious mutations resulting from fusion with genetically different individuals. However, the molecules responsible for allorecognition probably evolved gradually before the Cambrian period, and some other (external) factor remains to be identified as the missing triggering event. Sponge cells associate through calcium-dependent, multivalent carbohydrate-carbohydrate interactions of the g200 glycan found on extracellular proteoglycans. Single molecule force spectroscopy analysis of g200-g200 binding indicates that calcium affects the lifetime (+Ca/-Ca: 680 s/3 s) and bond reaction length (+Ca/-Ca: 3.47 Å/2.27 Å). Calculation of mean g200 dissociation times in low and high calcium within the theoretical framework of a cooperative binding model indicates the non-linear and divergent characteristics leading to either disaggregated cells or stable multicellular assemblies, respectively. This fundamental phenomenon can explain a switch from weak to strong adhesion between primitive metazoan cells caused by the well documented rise in ocean calcium levels at the end of Precambrian time. We propose that stronger cell adhesion allowed the integrity of genetically uniform animals composed only of “self” cells, facilitating genetic constitutions to remain within the metazoan individual and be passed down inheritance lines. The Cambrian explosion might have been triggered by the coincidence in time of primitive animals endowed with self/non-self recognition, and of a surge in sea water calcium that increased the binding forces between their calcium-dependent cell adhesion molecules.
Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Molecular Biology and Evolution 26 (2009): 2551-2561, doi:10.1093/molbev/msp170.
Suggested CitationPreprint: Fernandez-Busquets, Xavier, Kornig, Andre, Bucior, Iwona, Burger, Max M., Anselmetti, Dario, "Self-recognition and Ca2+-dependent carbohydrate–carbohydrate cell adhesion provide clues to the Cambrian explosion", 2009-07-17, https://doi.org/10.1093/molbev/msp170, https://hdl.handle.net/1912/3889
Showing items related by title, author, creator and subject.
Carbohydrate–carbohydrate interaction provides adhesion force and specificity for cellular recognition Bucior, Iwona; Scheuring, Simon; Engel, Andreas; Burger, Max M. (Rockefeller University Press, 2004-05-17)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 ...
Pold, Grace; Billings, Andrew F.; Blanchard, Jeffrey L.; Burkhardt, Daniel B.; Frey, Serita D.; Melillo, Jerry M.; Schnabel, Julia; van Diepen, Linda T. A.; DeAngelis, Kristen M. (American Society for Microbiology, 2016-09-02)As Earth's climate warms, soil carbon pools and the microbial communities that process them may change, altering the way in which carbon is recycled in soil. In this study, we used a combination of metagenomics and bacterial ...
Variability in the carbon isotopic composition of foliage carbon pools (soluble carbohydrates, waxes) and respiration fluxes in southeastern U.S. pine forests Mortazavi, Behzad; Conte, Maureen H.; Chanton, Jeffrey P.; Weber, John C.; Martin, Timothy A.; Cropper, Wendell P. (American Geophysical Union, 2012-04-19)We measured the δ13C of assimilated carbon (foliage organic matter (δCOM), soluble carbohydrates (δCSC), and waxes (δCW)) and respiratory carbon (foliage (δCFR), soil (δCSR) and ecosystem 13CO2 (δCER)) for two years at ...