The glucose transporter GLUT1 catalyses facilitative diffusion of glucose into erythrocytes and is responsible for glucose supply to the brain and other organs. Dysfunctional mutations may lead to GLUT1 deficiency syndrome, whereas overexpression of GLUT1 is a prognostic indicator for cancer. Despite decades of investigation, the structure of GLUT1 remains unknown. Here we report the crystal structure of human GLUT1 at 3.2 Å resolution. The full-length protein, which has a canonical major facilitator superfamily fold, is captured in an inward-open conformation. This structure allows accurate mapping and potential mechanistic interpretation of disease-associated mutations in GLUT1. Structure-based analysis of these mutations provides an insight into the alternating access mechanism of GLUT1 and other members of the sugar porter subfamily. Structural comparison of the uniporter GLUT1 with its bacterial homologue XylE, a proton-coupled xylose symporter, allows examination of the transport mechanisms of both passive facilitators and active transporters.

N(6)-methyladenosine (m(6)A) is the most abundant internal modification of nearly all eukaryotic mRNAs and has recently been reported to be recognized by the YTH domain family proteins. Here we present the crystal structures of the YTH domain of YTHDC1, a member of the YTH domain family, and its complex with an m(6)A-containing RNA. Our structural studies, together with transcriptome-wide identification of YTHDC1-binding sites and biochemical experiments, not only reveal the specific mode of m(6)A-YTH binding but also explain the preferential recognition of the GG(m(6)A)C sequences by YTHDC1.

The WD40 domain exhibits a β-propeller architecture, often comprising seven blades. The WD40 domain is one of the most abundant domains and also among the top interacting domains in eukaryotic genomes. In this review, we will discuss the identification, definition and architecture of the WD40 domains. WD40 domain proteins are involved in a large variety of cellular processes, in which WD40 domains function as a protein-protein or protein-DNA interaction platform. WD40 domain mediates molecular recognition events mainly through the smaller top surface, but also through the bottom surface and sides. So far, no WD40 domain has been found to display enzymatic activity. We will also discuss the different binding modes exhibited by the large versatile family of WD40 domain proteins. In the last part of this review, we will discuss how post-translational modifications are recognized by WD40 domain proteins.