UBA-like domain found in nascent polypeptide-associated complex subunit alpha (NACA) and similar proteins
The family contains nascent polypeptide-associated complex subunit alpha (NACA), putative NACA-like protein (NACP1), nascent polypeptide-associated complex subunit alpha domain-containing protein 1 (NACAD), and similar proteins found in archaea and bacteria. NACA, also called NAC-alpha or Alpha-NAC, together with BTF3, also called Beta-NAC, form the nascent polypeptide-associated complex (NAC) which is a cytosolic protein chaperone that contacts the nascent polypeptide chains as they emerge from the ribosome. Besides, NACA has a high affinity for nucleic acids and exists as part of several protein complexes playing a role in proliferation, apoptosis, or degradation. It is a cytokine-modulated specific transcript in the human TF-1 erythroleukemic cell line. It also acts as a transcriptional co-activator in osteoblasts by binding to phosphorylated c-Jun, a member of the activator-protein-1 (AP-1) family. Moreover, NACA binds to and regulates the adaptor protein Fas-associated death domain (FADD). In addition, NACA functions as a novel factor participating in the positive regulation of human erythroid-cell differentiation. The biological function of NACP1 (also called Alpha-NAC pseudogene 1 or NAC-alpha pseudogene 1) and NACAD remain unclear. The family also includes huntingtin-interacting protein K (HYPK), also called Huntingtin yeast partner K or Huntingtin yeast two-hybrid protein K. It is an intrinsically unstructured Huntingtin (HTT)-interacting protein with chaperone-like activity. It may be involved in regulating cell growth, cell cycle, unfolded protein response and cell death. All members in this family contain an ubiquitin-associated (UBA) domain.
Jiyao W et al.(2023). "The conserved domain database in 2023.",