Basic leucine zipper (bZIP) domain of bZIP transcription factors: a DNA-binding and dimerization domain; Basic leucine zipper (bZIP) factors comprise one of the most important classes of enhancer-type transcription factors. They act in networks of homo and heterodimers in the regulation of a diverse set of cellular processes including cell survival, learning and memory, lipid metabolism, and cancer progression, among others. They also play important roles in responses to stimuli or stress signals such as cytokines, genotoxic agents, or physiological stresses. The bZIP structural motif contains a basic region and a leucine zipper, composed of alpha helices with leucine residues 7 amino acids apart, which stabilize dimerization with a parallel leucine zipper domain. Dimerization of leucine zippers creates a pair of the adjacent basic regions that bind DNA and undergo conformational change. Dimerization occurs in a specific and predictable manner resulting in hundreds of dimers having unique effects on transcription.

                         10        20        30
                 ....*....|....*....|....*....|..
gi 568989644  93 KDRITKLEAAVKEAQEMAASQNKELSALRKEN 124
Cdd:cd14810   20 KEYITQLEEQVADRDAEIEQLRAELRALRNEN 51

zinc-RING finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 568989644    5 HCNQCFRK--DGAHFFVTSCGHIFCKKCMTLE----KCAVCG 40
Cdd:pfam14634   1 HCNKCFKElsKTRPFYLTSCGHIFCEECLTRLlqerQCPICK 42

RING finger, HC subclass, found in RING finger proteins RNF212, RNF212B and similar proteins; This subfamily includes RING finger protein RNF212, RNF212B, and their homologs. RNF212 is a dosage-sensitive regulator of crossing-over during mammalian meiosis. It plays a central role in designating crossover sites and coupling chromosome synapsis to the formation of crossover-specific recombination complexes. It also functions as an E3 ligase for small ubiquitin-related modifier (SUMO) modification. RNF212B shows high sequence similarity with RNF212, but its biological function remains unclear. Members of this subfamily contain an N-terminal C3HC4-type RING-HC finger. Also included are two homologs of RNF212, meiotic procrossover factors Zip3 and ZHP-3, which have been identified in Saccharomyces cerevisiae and Caenorhabditis elegans, respectively. Budding yeast Zip3 is a small ubiquitin-related modifier (SUMO) E3 ligase implicated in the SUMO pathway of post-translational modification. It sumoylates chromosome axis proteins, thus promoting synaptonemal complex polymerization. It also acts as an Smt3 E3 ligase. Zip3 includes a SUMO Interacting Motif (SIM) and a modified C3HCHC2-type RING-HC finger that are important for Zip3 in vitro E3 ligase activity and necessary for SC polymerization and correct sporulation. ZHP-3 acts at crossovers to couple meiotic recombination with synaptonemal complex disassembly and chiasma formation in Caenorhabditis elegans. It possesses a C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 568989644   4 FHCNQCFRKDG--AHFFVTSCGHIFCKKCMTL---EKCAVCG 40
Cdd:cd16560    1 VHCNTCFQLPGdtSKFFLTSCGHIYCDACVGKgkrNKCKICG 42

RING finger, HC subclass, found in RING finger protein 212 (RNF212) and similar proteins; RNF212 is a dosage-sensitive regulator of crossing-over during mammalian meiosis. It plays a central role in designating crossover sites and coupling chromosome synapsis to the formation of crossover-specific recombination complexes. It also functions as an E3 ligase for SUMO modification. RNF212 contains an N-terminal C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 568989644   3 WFHCNQCF---RKDGAHFFVTSCGHIFCKKCM---TLEKCAVCGNLCK 44
Cdd:cd16746    1 RVFCNFCFqqpRPNCPSFILTNCGHVVCEACLqkgKKNECLVCKAPCR 48

RING finger, HC subclass, found in RING finger protein 14 (RNF14) and similar proteins; RNF14, also known as androgen receptor-associated protein 54 (ARA54), HFB30, or Triad2 protein, is an RBR-type E3 ubiquitin-protein ligase that is highly expressed in the testis and interacts with class III E2s (UBE2E2, UbcH6, and UBE2E3). Its differential localization may play an important role in testicular development and spermatogenesis in humans. RNF14 functions as a transcriptional regulator of mitochondrial and immune function in muscle. It is a ligand-dependent androgen receptor (AR) co-activator and may also may participate in enhancing cell cycle progression and cell proliferation via induction of cyclin D1. Moreover, RNF14 is crucial for colon cancer cell survival. It acts as a new enhancer of the Wnt-dependent transcriptional outputs that acts at the level of the T-cell factor/lymphoid enhancer factor (TCF/LEF)-beta-catenin complex. RNF14 contains an N-terminal RWD domain and a C-terminal RBR domain. The RBR domain was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been corrected as RING-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR (RING1-BRcat-Rcat) domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase function to facilitate the ubiquitination reaction. This model corresponds to the RING domain, a C3HC4-type RING-HC finger required for RBR-mediated ubiquitination.

                         10        20        30
                 ....*....|....*....|....*....|...
gi 568989644   2 DWFHCNQCF-RKDGAHFF-VTSCGHIFCKKCMT 32
Cdd:cd16628    4 KIFTCNICFlDKLGSECMyFKDCGHVYCKECLK 36