The article "Classification of Intrinsically Disordered Regions and Proteins" by van der Lee et al. provides a comprehensive overview of intrinsically disordered regions (IDRs) and proteins, highlighting their functional significance and the need for classification. The authors discuss the challenges in characterizing uncharacterized protein segments, which often lack functional annotation and represent a significant source of functional novelty. They emphasize the importance of IDRs in various biological processes and their role in protein function, which can be either structured or disordered. The article is structured into several sections, covering topics such as the introduction, function, functional features, structure, sequence, protein interactions, evolution, regulation, and biophysical properties. It reviews different classification schemes for IDRs and proteins, including those based on function, structure, sequence, and interactions. The authors also discuss the functional classes of IDRs, such as entropic chains, display sites, chaperones, effectors, assemblers, and scavengers, and the molecular recognition features (MoRFs) that mediate specific protein-protein interactions. The article emphasizes the importance of understanding the structural and functional characteristics of IDRs and proteins, and the need for improved classification schemes to enhance function prediction and annotation. It concludes with a discussion on the current methods for function prediction of IDRs and IDPs, and suggests areas where increased efforts are needed to advance our understanding of protein disorder.The article "Classification of Intrinsically Disordered Regions and Proteins" by van der Lee et al. provides a comprehensive overview of intrinsically disordered regions (IDRs) and proteins, highlighting their functional significance and the need for classification. The authors discuss the challenges in characterizing uncharacterized protein segments, which often lack functional annotation and represent a significant source of functional novelty. They emphasize the importance of IDRs in various biological processes and their role in protein function, which can be either structured or disordered. The article is structured into several sections, covering topics such as the introduction, function, functional features, structure, sequence, protein interactions, evolution, regulation, and biophysical properties. It reviews different classification schemes for IDRs and proteins, including those based on function, structure, sequence, and interactions. The authors also discuss the functional classes of IDRs, such as entropic chains, display sites, chaperones, effectors, assemblers, and scavengers, and the molecular recognition features (MoRFs) that mediate specific protein-protein interactions. The article emphasizes the importance of understanding the structural and functional characteristics of IDRs and proteins, and the need for improved classification schemes to enhance function prediction and annotation. It concludes with a discussion on the current methods for function prediction of IDRs and IDPs, and suggests areas where increased efforts are needed to advance our understanding of protein disorder.