title: Scores of RINGS but no PHDs in ubiquitin signaling.
abstract: Recently, it has been reported that PHD fingers of MEKK1 kinase and a family of viral and cellular membrane proteins have E3 ubiquitin ligase activity. Here we describe unique sequence and structural signatures that distinguish PHD fingers from RING fingers, which function primarily as E3 ubiquitin ligases, and demonstrate that the Zn-binding modules of the above proteins are distinct versions of the RING domain rather than PHD fingers. Thus, currently available data reveal extreme versatility of RINGs and their derivatives that function as E3 ubiquitin ligases but provide no evidence of this activity among PHD fingers whose principal function appears to involve specific protein-protein and possibly protein-DNA interactions in chromatin.
authors.affiliation: National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA.
authors.forename: L
authors.initials: L
authors.lastname: Aravind
authors.forename: L M
authors.initials: LM
authors.lastname: Iyer
authors.forename: E V
authors.initials: EV
authors.lastname: Koonin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D008954:Models, Biological; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D015398:Signal Transduction; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry* / Q000502:physiology; D014452:Ubiquitins / Q000378:metabolism*; D016335:Zinc Fingers
chemical_list: D014452:Ubiquitins; D044767:Ubiquitin-Protein Ligases