UBA domain-like superfamily; The ubiquitin-associated (UBA) domain-like superfamily contains alpha-helical structural homology ubiquitin-binding domains, including UBA domains and coupling of ubiquitin conjugation to endoplasmic reticulum degradation (CUE) domains which share a common three-helical bundle architecture. UBA domains are commonly occurring sequence motifs found in proteins involved in ubiquitin-mediated proteolysis. They contribute to ubiquitin (Ub) binding or ubiquitin-like (UbL) domain binding. However, some kinds of UBA domains can only bind the UbL domain, but not the Ub domain. UBA domains are normally comprised of compact three-helix bundles which contain a conserved GF/Y-loop. They can bind polyubiquitin with high affinity. They also bind monoubiquitin and other proteins. Most UBA domain-containing proteins have one UBA domain, but some harbor two or three UBA domains. CUE domain containing proteins are characterized by an FP and a di-leucine-like sequence and bind to monoubiquitin with varying affinities. Some higher eukaryotic CUE domain proteins do not bind monoubiquitin efficiently, since they carry LP, rather than FP among CUE domains. This superfamily also includes many UBA-like domains found in AMP-activated protein kinase (AMPK) related kinases, the NXF family of mRNA nuclear export factors, elongation factor Ts (EF-Ts), nascent polypeptide-associated complex subunit alpha (NACA) and similar proteins. Although many UBA-like domains may have a conserved TG but not GF/Y-loop, they still show a high level of structural and sequence similarity with three-helical ubiquitin binding domains.

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gi 24644954 373 RFTEQLRTMAAMGFINHTQNVSYLELSDGNVEHAINLL 410
Cdd:cd14399   1 RYASQLEQLQAMGFVDRQANIQALIATGGNVNAAIERL 38

UBA domain of eukaryotic protein linking integrin-associated protein (IAP, also known as CD47) with cytoskeleton (PLIC) proteins; The PLIC proteins (or ubiquilins) family contains human homologs of the yeast ubiquitin-like Dsk2 protein, PLIC-1 (also called ubiquilin-1), PLIC-2 (also called ubiquilin-2 or Chap1), PLIC-3 (also called ubiquilin-3) and PLIC-4 (also called ubiquilin-4, Ataxin-1 interacting ubiquitin-like protein, A1Up, Connexin43-interacting protein of 75 kDa, or CIP75), and mouse PLIC proteins. They are ubiquitin-binding adaptor proteins involved in all protein degradation pathways through delivering ubiquitinated substrates to proteasomes. They also promote autophagy-dependent cell survival during nutrient starvation. PLIC-1 regulates the function of the thrombospondin receptor CD47 and G protein signaling. It plays a role in TLR4-mediated signaling through interacting with the Toll/interleukin-1 receptor (TIR) domain of TLR4. It also inhibits the TLR3-Trif antiviral pathway by reducing the abundance of Trif. Moreover, PLIC-1 binds to gamma-aminobutyric acid receptors (GABAARs) and modulates the ubiquitin-dependent, proteasomal degradation of GABAARs. Furthermore, PLIC-1 acts as a molecular chaperone regulating amyloid precursor protein (APP) biosynthesis, trafficking, and degradation by stimulating K63-linked polyubiquitination of lysine 688 in the APP intracellular domain. In addition, PLIC-1 is involved in the protein aggregation-stress pathway via associating with the ubiquitin-interacting motif (UIM) proteins ataxin 3, HSJ1a, and epidermal growth factor substrate 15 (EPS15). PLIC-2 is a protein that binds the ATPase domain of the HSP70-like Stch protein. It functions as a negative regulator of G protein-coupled receptor (GPCR) endocytosis. It also involved in amyotrophic lateral sclerosis (ALS)-related dementia. PLIC-3 is encoded by UBQLN3, a testis-specific gene. It shows high sequence similarity with the Xenopus protein XDRP1, a nuclear phosphoprotein that binds to the N-terminus of cyclin A and inhibits Ca2+-induced degradation of cyclin A, but not cyclin B. PLIC-4 is a ubiquitin-like nuclear protein that interacts with ataxin-1 and further links ataxin-1 with the chaperone and ubiquitin-proteasome pathways. It also binds to the non-ubiquitinated gap junction protein connexin43 (Cx43) and regulates the turnover of Cx43 through the proteasomal pathway. PLIC proteins contain an N-terminal ubiquitin-like (UBL) domain that is responsible for the binding of ubiquitin-interacting motifs (UIMs) expressed by proteasomes and endocytic adaptors, and C-terminal ubiquitin-associated (UBA) domain that interacts with ubiquitin chains present on proteins destined for proteasomal degradation. In addition, mammalian PLIC2 proteins have an extra collagen-like motif region which is absent in other PLIC proteins and the yeast Dsk2 protein.

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gi 24644954 373 RFTEQLRTMAAMGFINHTQNVSYLELSDGNVEHAINLL 410
Cdd:cd14399   1 RYASQLEQLQAMGFVDRQANIQALIATGGNVNAAIERL 38

UBA domain of eukaryotic protein linking integrin-associated protein (IAP, also known as CD47) with cytoskeleton (PLIC) proteins; The PLIC proteins (or ubiquilins) family contains human homologs of the yeast ubiquitin-like Dsk2 protein, PLIC-1 (also called ubiquilin-1), PLIC-2 (also called ubiquilin-2 or Chap1), PLIC-3 (also called ubiquilin-3) and PLIC-4 (also called ubiquilin-4, Ataxin-1 interacting ubiquitin-like protein, A1Up, Connexin43-interacting protein of 75 kDa, or CIP75), and mouse PLIC proteins. They are ubiquitin-binding adaptor proteins involved in all protein degradation pathways through delivering ubiquitinated substrates to proteasomes. They also promote autophagy-dependent cell survival during nutrient starvation. PLIC-1 regulates the function of the thrombospondin receptor CD47 and G protein signaling. It plays a role in TLR4-mediated signaling through interacting with the Toll/interleukin-1 receptor (TIR) domain of TLR4. It also inhibits the TLR3-Trif antiviral pathway by reducing the abundance of Trif. Moreover, PLIC-1 binds to gamma-aminobutyric acid receptors (GABAARs) and modulates the ubiquitin-dependent, proteasomal degradation of GABAARs. Furthermore, PLIC-1 acts as a molecular chaperone regulating amyloid precursor protein (APP) biosynthesis, trafficking, and degradation by stimulating K63-linked polyubiquitination of lysine 688 in the APP intracellular domain. In addition, PLIC-1 is involved in the protein aggregation-stress pathway via associating with the ubiquitin-interacting motif (UIM) proteins ataxin 3, HSJ1a, and epidermal growth factor substrate 15 (EPS15). PLIC-2 is a protein that binds the ATPase domain of the HSP70-like Stch protein. It functions as a negative regulator of G protein-coupled receptor (GPCR) endocytosis. It also involved in amyotrophic lateral sclerosis (ALS)-related dementia. PLIC-3 is encoded by UBQLN3, a testis-specific gene. It shows high sequence similarity with the Xenopus protein XDRP1, a nuclear phosphoprotein that binds to the N-terminus of cyclin A and inhibits Ca2+-induced degradation of cyclin A, but not cyclin B. PLIC-4 is a ubiquitin-like nuclear protein that interacts with ataxin-1 and further links ataxin-1 with the chaperone and ubiquitin-proteasome pathways. It also binds to the non-ubiquitinated gap junction protein connexin43 (Cx43) and regulates the turnover of Cx43 through the proteasomal pathway. PLIC proteins contain an N-terminal ubiquitin-like (UBL) domain that is responsible for the binding of ubiquitin-interacting motifs (UIMs) expressed by proteasomes and endocytic adaptors, and C-terminal ubiquitin-associated (UBA) domain that interacts with ubiquitin chains present on proteins destined for proteasomal degradation. In addition, mammalian PLIC2 proteins have an extra collagen-like motif region which is absent in other PLIC proteins and the yeast Dsk2 protein.

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gi 24644954 373 RFTEQLRTMAAMGFINHTQNVSYLELSDGNVEHAINLL 410
Cdd:cd14399   1 RYASQLEQLQAMGFVDRQANIQALIATGGNVNAAIERL 38

UBA domain of Saccharomyces cerevisiae proteasome interacting protein Dsk2p and its homologs found in fungi; The family contains several fungal multi-ubiquitin receptors, including Saccharomyces cerevisiae Dsk2p and Schizosaccharomyces pombe Dph1p, both of which have been characterized as shuttle proteins transporting ubiquitinated substrates destined for degradation from the E3 ligase to the 26S proteasome. They interact with the proteasome through their N-terminal ubiquitin-like domain (UBL) and with ubiquitin (Ub) through their C-terminal ubiquitin-associated domain (UBA). S. cerevisiae Dsk2p is a nuclear-enriched protein that may involve in the ubiquitin-proteasome proteolytic pathway through interacting with K48-linked polyubiquitin and the proteasome. Moreover, it has been implicated in spindle pole duplication through assisting in Cdc31 assembly into the new spindle pole body (SPB). S. pombe Dph1p is a ubiquitin receptor working in concert with the class V myosin, Myo52, to target the degradation of the S. pombe CLIP-170 homolog, Tip1. It also can protect ubiquitin chains against disassembly by deubiquitinating enzymes.

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gi 24644954 371 RHRFTEQLRTMAAMGFINHTQNVSYLELSDGNVEHAINLLM 411
Cdd:cd14324   2 EERYEEQLRQLNEMGFFDFDRNVRALRRSGGSVQGAVESLL 42

ubiquitin-like (Ubl) domain found in ubiquitin and ubiquitin-like Ubl proteins; Ubiquitin-like (Ubl) proteins have a similar ubiquitin (Ub) beta-grasp fold and attach to other proteins in a Ubl manner but with biochemically distinct roles. Ub and Ubl proteins conjugate and deconjugate via ligases and peptidases to covalently modify target polypeptides. Some Ubl domains have adaptor roles in Ub-signaling by mediating protein-protein interaction. Prokaryotic sulfur carrier proteins are Ub-related proteins that can be activated in an ATP-dependent manner. Polyubiquitination signals for a diverse set of cellular events via different isopeptide linkages formed between the C terminus of one ubiquitin (Ub) and the epsilon-amine of K6, K11, K27, K29, K33, K48, or K63 of a second Ub. One of these seven lysine residues (K27, Ub numbering) is conserved in this Ubl_ubiquitin_like family. K27-linked Ub chains are versatile and can be recognized by several downstream receptor proteins. K27 has roles beyond chain linkage, such as in Ubl NEDD8 (which contains many of the same lysines (K6, K11, K27, K33, K48) as Ub) where K27 has a role (other than conjugation) in the mechanism of protein neddylation.

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gi 24644954   9 KNKLSDVHPLHnIDLTRDVAYLKAVVTKEmhLQFDASELEIIHHGRVLEDADTLNRT-LQPNAVIHCF 75
Cdd:cd17039   4 KTLDGKTYTVE-VDPDDTVADLKEKIEEK--TGIPVEQQRLIYNGKELKDDKTLSDYgIKDGSTIHLV 68