ubiquitin-like (Ubl) domain found in the eukaryotic Ddi1 family
The eukaryotic Ddi1 family, including yeast aspartyl protease DNA-damage inducible 1 (Ddi1) and Ddi1-like proteins from vertebrates and other eukaryotes, has been characterized by containing an N-terminal ubiquitin-like (Ubl) domain and a conserved retroviral aspartyl-protease-like domain (RVP) that is important in cell-cycle control. Yeast Ddi1 and many family members also contain a C-terminal ubiquitin-association (UBA) domain, however, Ddi1-like proteins from all vertebrates lack the UBA domain. Ddi1, also termed v-SNARE-master 1 (Vsm1), is an ubiquitin receptor involved in the cell cycle and late secretory pathway in Saccharomyces cerevisiae. It functions as an UBA-Ubl shuttle protein that is required for the proteasome to enable ubiquitin-dependent degradation of its ligands. For instance, Ddi1 plays an essential role in the final stages of proteasomal degradation of Ho endonuclease and of its cognate FBP, Ufo1. Moreover, Ddi1 and its associated protein Rad23p play a cooperative role as negative regulators in yeast PHO pathway. This family also includes mammalian regulatory solute carrier protein family 1 member 1 (RSC1A1), also termed transporter regulator RS1 (RS1), which mediates transcriptional and post-transcriptional regulation of Na(+)-D-glucose cotransporter SGLT1. Ddi1-like proteins play a significant role in cell cycle control, growth control, and trafficking in yeast and may play a crucial role in embryogenesis in higher eukaryotes.
Feature 1: key conserved lysine K27, 1 residue position
Conserved feature residue pattern:[KR]
Evidence:
Comment:K27 (Ub numbering) is a lysine conserved in the Ubl_ubiquitin_like family, and mostly conserved in this subfamily (K/R); it is one of 7 lysines involved in chain linkage in ubiquitin (K6, K11, K27, K29, K33, K48, or K63, Ub numbering), the other 6 lysines are not conserved in this subfamily; may have other functions
Jiyao W et al.(2023). "The conserved domain database in 2023.",