The biodiversity of KS-proteoglycans in cellular regulation and tissue function: emerging bioregulatory roles for low sulfation proteoglycans and bioconjugates.

The aim of this study was to illustrate the biodiverse properties of keratan sulfate (KS) proteoglycans (PGs), their varied functions in tissues, and emerging roles for low sulfation isoforms of KSPGs now detectable due to the development of some novel KS antibodies. KS is a glycosaminoglycan (GAG), of diverse structure and functional properties and decorates a large range of PGs and equips these with cell regulatory properties. KSPGs also have biophysical roles in tissue stabilization and specific roles in electroconductive bioregulation of neural processes controlling tissue functions. Compared with the multitude of studies on other GAGs, KS has been rather neglected. In the past, the major focus was on the biology of high charge density isoforms of KS. In the present day, the development of antibodies that can now detect low sulfation isoforms of KS have demonstrated their potential roles in novel cell regulatory processes adding to the diverse bioregulatory properties of KSPGs. KS and KSPGs are now entering new areas in bioregulation adding to the functional roles of PGs in the regulation of connective tissue form and function in health and disease.