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Ubiquilin-2, also known as UBQLN2 contains an N-terminal ubiquitin-like domain and a C-terminal ubiquitin-associated domain. UBQLN2 is physically linked with proteasomes as well as ubiquitin ligases, and therefore is considered to functionally connect the ubiquitination machinery to the proteasome in order to affect in vivo protein degradation. Furthermore, UBQLN2 binds the ATPase domain of the Hsp70-like Stch protein. Among the diseases which are associated with UBQLN2: Amyotrophic lateral sclerosis 15, with or without frontotemporal dementia as well as Amyotrophic lateral sclerosis type 15.

TNFR2 belongs to the TNF-receptor superfamily. TNFR2 is receptor with high affinity for TNFSF2/TNF-alpha and approximately 5-fold lower affinity for homotrimeric TNFSF1/lymphotoxin-alpha. TNFR2 mediates the majority of the metabolic effects of TNF-alpha. In addition, knockout studies in mice propose a role for TNFR2 in protecting neurons from apoptosis by stimulating antioxidative pathways. TNFR2 expression might have a significant role in the angiogenesis, tumor cell proliferation and metastasis of Invasive micropapillary carcinoma of the breast.
There are 2 types of soluble TNF receptors: sTNFR-I and sTNFR-II, which act to neutralize the biological activities of TNF alpha and TNF beta. The levels of these soluble receptors seem to increase as a result of shedding of the extracellular domains of the membrane bound receptors. High levels of soluble TNF receptors are found in the amniotic fluid of pregnant women. TNFR2 and TNFR1 form a heterocomplex which mediates the recruitment of 2 anti-apoptotic proteins, c-IAP1 and c-IAP2, which possess E3 ubiquitin ligase activity. IAPs’ function in TNF-receptor signaling is unknown; nevertheless, c-IAP1 is believed to potentiate TNF-induced apoptosis by the ubiquitination and degradation of TNF-receptor-associated factor 2, which mediates anti-apoptotic signals. Oxidative stress promotes TNFR1 and TNFR2 self-interaction, ligand-independent and enhanced ligand-dependent TNF signaling. TNF-a, TNFR1 and TNFR2 have roles in cellular differentiation. TNFR1 and TNFR2 function in cell type-specific renal injury.

REV1 Polymerase (REV1) contains a BRCT domain, which is imperative in protein-protein interactions. REV1 is a deoxycytidyl transferase involved in DNA repair. REV1 assists in the 1st step in the bypass of abasic lesions by the incorporation of a nucleotide opposite the lesion. REV1 is essential for normal generation of mutations by physical and chemical agents. REV1 transfers a dCMP residue from dCTP to the 3'-end of a DNA primer in a template-dependent reaction. A role for the human Rev1-like protein has been suggested as a scaffold which recruits DNA polymerases involved in translesion synthesis (TLS) of damaged DNA.

Transthyretin (TTR) is a circulating and abundant tetramer, which functions as a carrier protein of thyroid hormone and retinol binding protein. It is primarily produced in the liver, but also in the brain and eye. Mutations in the TTR gene cause the protein to dissociate into monomers that after misfolding assemble into amyloid fibrils deposits in a variety of organs. TTR is also the only gene known to be associated with familial TTR amyloidosis. The diseases that originate from mutations in the TTR gene include amyloidotic polyneuropathy, euthyroid hyperthyroxinaemia, amyloidotic vitreous opacities, cardiomyopathy, oculoleptomeningeal amyloidosis, meningocerebrovascular amyloidosis, carpal tunnel syndrome, etc.

ARF1 is a small guanine nucleotide-binding protein that increases the enzymatic activities of cholera toxin. ARF1 is necessary and ubiquitous in eukaryotes. ARF1 takes part in vesicular transport and functioning via phospholipase D activation. ARF1 is involved in membrane traffic and organelle integrity which are closely tied to their reversible association with membranes and distinct interactions with membrane phospholipids.

Small Ubiquitin-like Modifiers (SUMOs) are a family of small, related proteins that can be enzymatically attached to a target protein by a post-translational modification process termed sumoylation. Unlike ubiquitination, which targets proteins for degradation, sumoylation participates in a number of cellular processes, such as nuclear transport, transcriptional regulation, apoptosis, and protein stability. All SUMO proteins share the conserved ubiquitin domain and the C-terminal diglycine cleavage/attachment site. Human SUMO2, also known as Sentrin2 and SMT3B is synthesized as a 95 amino acid (aa), 11 kDa propeptide that contains a two aa C-terminal prosegment, and an 18 aa N-terminal protein interacting region (aa 33 -50). Following prosegment cleavage, the C-terminal glycine is enzymatically attached to a lysine on a target protein. Human SUMO2 shares 100% sequence identity to SUMO-2 from mouse. SUMO2 also has very high sequence homology to SUMO3 and SUMO4, 86 % and 85%, respectivel

EIF5A is the single protein identified to contain remarkable amino acid formed by the action of deoxyhypusine synthase and deoxyhypusine hydroxylase using spermidine as the substrate. EIF5A takes part in the first step of peptide bond formation in translation, nevertheless further experiments implicates it as a universally conserved translation elongation factor. Modulation of EIF5A is connected to proliferation and cancer. Expression of EIF-5A is upregulated in the PBMCs of HIV-1 patients. EIF5A coordinates significant cellular processes like cell viability and senescence during its effects on the stability of certain mRNAs. Heat stress-induced loss of EIF-5A in a human pancreatic cancer cell line. EIF5A stability takes part in determining the fate of the particular cell type after severe heat stress.

Ecto-5-prime-nucleotidase (5-prime-ribonucleotide phosphohydrolase) catalyzes the conversion of purine 5-prime mononucleotides to nucleosides, the preferred substrate being AMP at a neutral pH. CD73, which consists of a dimer of 2 identical 70kDa subunits, is bound by a glycosyl phosphatidyl inositol linkage to the external face of the plasma membrane. CD73 is used as a marker of lymphocyte differentiation. Consequently, a deficiency of NT5 occurs in a variety of immunodeficiency diseases. Additional forms of 5-prime nucleotidase exist in the cytoplasm and lysosomes and can be distinguished from ecto-NT5 by their substrate affinities, requirement for divalent magnesium ion, activation by ATP, and inhibition by inorganic phosphate.

CIAO1 is a vital component of the cytosolic iron-sulfur (Fe/S) protein assembly machinery. CIAO1 protein is required for the maturation of extra mitochondrial Fe/S proteins and seems to specifically modulate the trans-activation activity of WT1. CIAO1 participates in chromosome segregation as a part of the mitotic spindle-associated MMXD complex.

SARS Coronavirus is an enveloped virus containing three outer structural proteins, namely the membrane (M), envelope (E), and spike (S) proteins. Spike (S)-glycoprotein of the virus interacts with a cellular receptor and mediates membrane fusion to allow viral entry into susceptible target cells. Accordingly, S-protein plays an important role in virus infection cycle and is the primary target of neutralizing antibodies.
It has recently been shown that SARS (severe acute respiratory syndrome) is caused by a human coronavirus. Human coronaviruses are the major cause of upper respiratory tract illness, such as the common cold, in humans. Coronaviruses are positive-stranded RNA viruses, featuring the largest viral RNA genomes known to date (27-31 kb). The first step in coronavirus infection is binding of the viral spike protein, a 139-kDa protein, to certain receptors on host cells. The spike protein is the main surface antigen of the coronavirus. The glycosilated spike protein (as well as the nucleocapsid protein) can be detected in infected cell culture supernatants with antisera from SARS patients.

RAB5A is a member of RAS oncogene family. The small GTPase, RAB5A is a crucial regulatory component of the endocytic pathway. Activation of RAB5A is mediated by GDP-GTP exchange factors (GEFs) that generate the Rab5-GTP complex). RAB5A is required for the fusion of plasma membranes and early endosomes.

AICDA is an RNA-editing deaminase which belongs to the cytidine deaminase family. AICDA is involved in somatic hypermutation, gene conversion, and class-switch recombination of immunoglobulin genes. Defects in the AICDA gene are the cause of autosomal recessive hyper-IgM immunodeficiency syndrome type 2 (HIGM2).

CKMT1A is in charge of the transfer of high energy phosphate from mitochondria to the cytosolic carrier, creatine. CKMT1A is a member of the creatine kinase isoenzyme family and exists as two isoenzymes, sarcomeric MtCK and ubiquitous MtCK, encoded by separate genes. Mitochondrial creatine kinase arises in two different oligomeric forms: dimers and octamers, unlike the exclusively dimeric cytosolic creatine kinase isoenzymes. Numerous malignant cancers with poor prognosis have displayed overexpression of ubiquitous mitochondrial creatine kinase which is linked to high energy turnover and inability to remove cancer cells through apoptosis.