Mammalian sugar-binding receptors: known functions and unexplored roles.

Maureen E. Taylor,Kurt Drickamer

doi:10.1111/febs.14759

Abstract

Mammalian glycan‐binding receptors, sometimes known as lectins, interact with glycans, the oligosaccharide portions of endogenous mammalian glycoproteins and glycolipids as well as sugars on the surfaces of microbes. These receptors guide glycoproteins out of and back into cells, facilitate communication between cells through both adhesion and signaling, and allow the innate immune system to respond quickly to viral, fungal, bacterial, and parasitic pathogens. For many of the roughly 100 glycan‐binding receptors that are known in humans, there are good descriptions of what types of glycans they bind and how selectivity for these ligands is achieved at the molecular level. In some cases, there is also comprehensive evidence for the roles that the receptors play at the cellular and organismal levels. In addition to highlighting these well‐understood paradigms for glycan‐binding receptors, this review will suggest where gaps remain in our understanding of the physiological functions that they can serve.

Highlights

In the nearly 50 years since the discovery of the first mammalian glycan-binding protein, more than a hundred additional receptors have been described
The fact that the selectins and the mannose receptor have been successfully targeted for development of anti-inflammatory therapy and for treatment of lysosomal storage diseases provides paradigms for how knowledge of the mechanisms and physiological functions of additional sugar-binding receptors will provide a basis for additional therapeutic applications

Summary

Introduction

In the nearly 50 years since the discovery of the first mammalian glycan-binding protein, more than a hundred additional receptors have been described. For many of the receptors, it is known how they bind selected oligosaccharide structures and the current state of our molecular understanding of what types of proteins bind glycans and how they achieve selectivity has been recently assessed [1]. The goal of this review was to summarize briefly the repertoire of glycan-binding receptors and to focus on the current state of knowledge in five areas that encompass the major biological functions of these receptors. There are at least some cases in which we can describe in detail how receptors mediate essential physiological functions of glycans in humans and other mammals. An update on the repertoire of glycan-binding receptors Important areas remain to be fully explored, so gaps in our understanding and recent results that help to fill in some of these gaps will be highlighted in each section.

Objectives

Conclusion