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SDCBP2 has two class II PDZ domains. PDZ domains assist protein-protein interactions by attaching to the cytoplasmic C-terminus of transmembrane proteins, and PDZ-containing proteins mediate cell signaling and the organization of protein complexes. SDCBP2 attaches to phosphatidylinositol 4, 5-bisphosphate (PIP2) and take part in nuclear PIP2 arrangement and cell division.

IFIH1 is a DEAD box protein which is upregulated in response to treatment with beta-interferon and a protein kinase C-activating compound, mezerein. Irreversible reprogramming of melanomas can be attained by therapy with both these agents; treatment with either agent alone only achieves reversible differentiation. DEAD box proteins are implicated in several cellular processes involving alteration of RNA secondary structure such as translation initiation, nuclear and mitochondrial splicing, and ribosome and spliceosome assembly.

Trafficking protein particle complex 4 (TRAPPC4) is part of the multisubunit TRAPP (transport protein particle) complex and interacts with SDC2. TRAPPC4 has a role in vesicular transport from endoplasmic reticulum to Golgi.

Syndecan-4 is a type I integral membrane heparan sulfate proteoglycan (HSPG), which was originally isolated from cloned rat microvascular endothelial cells as an antithrombin-binding molecule, and is now known to be a member of the syndecan family. Syndecan-4 binds to basic fibroblast growth factor (bFGF), midkine, and tissue factor pathway inhibitor via its heparan sulfate chains, and is thought to be involved in various biologic functions such as signaling of bFGF, anticoagulation, and focal adhesion formation. A previous study demonstrated that syndecan-4 is expressed in various tissues, and its level of expression in the kidney is stronger than those of other syndecan family members. Thus, syndecan-4 is thought to play certain roles in maintaining renal function. Moreover, it has been reported that proteoglycans, especially sulfated proteoglycans, are involved in organogenesis of the kidney.

TRIM21 is a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. The 52 kDa Ro protein is part of the RoSSA ribonucleoprotein, which includes a single polypeptide and one of four small RNA molecules. The RoSSA particle localizes to both the cytoplasm and the nucleus. Ro/SSA interacts with autoantigens in patients with Sjogren syndrome and systemic lupus erythematosus. Ribonucleoprotein particle is composed of a single polypeptide and one of four small RNA molecules. The RoSSA is present in all mammalian cells studied but has no known function. At least 2 isoforms are present in nucleated and red blood cells, and tissue specific differences in Ro/SSA proteins were identified.

VAMP4 belongs to the synaptobrevin family who are involved in docking and/or fusion of vesicles with cell membrane. VAMP4 is enriched in the trans-Golgi network and may be a factor in the trans-Golgi network-to-endosome transport. VAMP4 is involved in the pathway which functions to eliminate an inhibitor (most likely synaptotagmin-4) of calcium-triggered exocytosis during the maturation of secretory granules. Synaptobrevins, syntaxins, and SNAP25 are the chief components of a protein complex involved in the docking and/or fusion of synaptic vesicles with the presynaptic membrane.

STX6 is a member of the syntaxin family and has 1 t-SNARE coiled-coil homology domain. STX6 takes part in intracellular vesicle transferring. STX6 binds EEA1 and Interacts with VPS45A, MARCH2, MARCH3 and GOPC. It is found in a complex comprising STX6, STX12, VAMP4 and VTI1A.

Synaptobrevin 1(Vehicle-associated membrane, VAMP1) is one of the key proteins in the SNARE complex which is involved in regulated exocytosis. Synaptobrevin1 binds to t-SNAREs, syntaxin (STX) and SNAP25, after the fusion of synaptic vesicles to plasma membrane.

SRGN is identified as a hematopoietic cell granule proteoglycan. Proteoglycans stored in the secretory granules of various hematopoietic cells also hold a protease-resistant peptide core, and is vital for neutralizing hydrolytic enzymes. SRGN is related to the macromolecular complex of granzymes and perforin that acts as a intermediary of granule-mediated apoptosis.

Synaptobrevin 2 which is an 18 kDa integral membrane protein localized to the cytoplasmic surface of synaptic vesicle, consists of a proline-rich N-terminal region, a highly conserved hydrophilic domain, followed by a transmembrane anchor and a C-terminal. Synaptobrevin 2 is predominantly expressed in Langerhans islets and glomerular cells. The N-terminal domain of the protein (residues 1-89) forms a specific SNARE complex with the target membrane-associated t- or Q-SNAREs syntaxin 1 and SNAP-25.

MANF is a 20kDa protein which belongs to the ARMET family. MANF was originally known as an arginine-rich region protein which was extremely mutated in a large number of tumors. MANF Expression is induced during ER stress, signifying that MANF takes part in protein quality control during ER stress.

GNLY is part of the SAPLIP family and is located in the cytotoxic granules of T cells, which are discharged upon antigen stimulation. GNLY is localized in cytotoxic granules of cytotoxic T lymphocytes and natural killer cells, and it has antimicrobial activity against M. tuberculosis and other organisms. GNLY is an antimicrobial protein that kills intracellular pathogens. GNLY is active against a wide range of microbes, including Gram-positive and Gram-negative bacteria, fungi, and parasites. Kills Mycobacterium tuberculosis.

Syntaxin 3 (STX3) is a member of the syntaxin family. The syntaxin family members are cellular receptors for transport vesicles which participate in exocytosis in neutrophils. STX3 has a significant role in the growth of neurites and functions as a direct target for omega-6 arachidonic acid. STX3 is steered to the apical membrane of epithelial cells where it forms clusters and is vital in establishing and maintaining polarity required for protein trafficking involving vesicle fusion and exocytosis.

The 14-3-3 family of proteins plays a key regulatory role in signal transduction, checkpoint control, apoptotic and nutrient-sensing pathways. 14-3-3 proteins are highly conserved and ubiquitously expressed. There are at least seven isoforms that have been identified in mammals. The 14-3-3gamma, a subtype of the 14-3-3 family of proteins, was thought to be brain and neuron-specific. It has been shown to interact with RAF1 and protein kinase C, proteins involved in various signal transduction pathways.

Synovial Sarcoma, X Breakpoint 1 (SSX1) is a member of a family of highly homologous synovial sarcoma X (SSX) breakpoint proteins. SSX proteins are localized to the nucleus and expressed in testis and some types of cancers and, hence, they are classified as C/T (cancer/testis) antigens. These proteins may serve as transcriptional repressors. SSX1 genes are involved in the t (X;18) translocation typically found in all synovial sarcomas. This translocation leads to the fusion of the synovial sarcoma translocation gene on chromosome 18 to one of the SSX genes on chromosome X. These hybrid proteins are most likely responsible for transforming activity.

SIL1 is localized to endoplasmic reticulum (ER). SIL1 is an N-linked glycoprotein with an N-terminal ER targeting sequence, 2 putative N-glycosylation sites, and a C-terminal ER retention signal. SIL1 acts as a nucleotide exchange factor for another unfolded protein response protein. Mutations in SIL1 are linked to Marinesco-Sjogren syndrome.

Ro 60 kDa autoantigen is an RNA-binding protein that binds to several small cytoplasmic RNA molecules known as Y RNAs. SSA2 may stabilize these RNAs from degradation. Sera taken from patients with Systemic Lupus Erythematosus (SLE) often contains antibodies that react with the normal cellular SSA2 protein as if this antigen was foreign.

Pre-mRNA-splicing factor SYF2 (SYF2) may be involved in pre-mRNA splicing. The SYF2 protein interacts with cyclin D-type binding-protein 1, which is believed to be a cell cycle regulator at the G1/S transition. SYF2 is amply expressed in the heart, skeletal muscle and kidney and is expressed at lower levels in other tissues.

Syntaxin 4 (STX4) is a member of the syntaxin/epimorphin family of proteins. The Syntaxin family is cellular receptors for transport vesicles which participate in exocytosis in neutrophils. Syntaxin 4 is vital for normal regulation of glucose metabolism uptake in skeletal muscle and decline in STX4 protein levels lead to reduction of whole-body hormone-stimulated glucose metabolism. STX4 is expressed in neutrophils and neutrophil-differentiated HL-60 cells. The STX4 expression in neutrophils increases with differentiation.

Syntaxin-2 (STX2) is a member of the syntaxin/epimorphin family of proteins. Syntaxin family members are cellular receptors for transport vesicles which participate in exocytosis in neutrophils. STX2 regulates epithelial-mesenchymal interactions and epithelial cell morphogenesis and activation. STX2 is a t-SNARE which localizes to the apical plasma membrane and intracellular vesicular structures. In addition, STX2, along with SNAP-23, is essential for regulated surfactant secretion.

Syntaxin-binding protein 6 (STXBP6) binds components of the SNARE complex and takes part in regulating SNARE complex configuration. STXBP6 forms non-fusogenic complexes with SNAP25 and STX1A and modulates the formation of SNARE complexes and exocytosis.

The 26S proteasome is a multicatalytic proteinase complex with a well ordered structure composed of two complexes- a 20S core and a 19S regulator. PSMD11 is a non-ATPase subunit of the 19S regulator. The 20S core is composed of four rings of 28 non-identical subunits; two rings are composed of 7 alpha subunits and two rings are composed of 7 beta subunits. The 19S regulator is composed of a base that contains six ATPase subunits and two non-ATPase subunits, and a lid that contains up to ten non-ATPase subunits. Proteasomes are spread throughout eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. An indispensable function of a modified proteasome, the immunoproteasome, is the processing of class I MHC peptides.

Proteasome 26S Subunit, Non-ATPase 13 (PSMD13) is a part of the proteasome subunit S11 family and contains one PCI domain. PSMD13 plays a role as a regulatory subunit of the 26S proteasome which takes part in the ATP-dependent degradation of ubiquitinated proteins.

Clusterin also named Apolipoprotein J (APO-J) is a 75-80 kD disulfide-linked heterodimeric protein containing about 30% of N-linked carbohydrate rich in sialic acid but truncated forms targeted to the nucleus have also been identified.
The precursor polypeptide chain is cleaved proteolytically to remove the 22-mer secretory signal peptide and subsequently between residues 227/228 to generate the a and b chains. These are assembled in anti-parallel to give a heterodimeric molecule in which the cysteine-rich centers are linked by five disulfide bridges and are flanked by two predicted coiled-coil a-helices and three predicted amphipathic a-helices.
Across a broad range of species clusterin shows a high degree of sequence homology ranging from 70% to 80%. It is nearly ubiquitously expressed in most mammalian tissues and can be found in plasma, milk, urine, cerebrospinal fluid and semen.
It is able to bind and form complexes with numerous partners such as immunoglobulins, lipids, heparin, bacteria, complement components, paraoxonase, beta amyloid, leptin and others. Clusterin has been ascribed a plethora of functions such as phagocyte recruitment, aggregation induction, complement attack prevention, apoptosis inhibition, membrane remodeling, lipid transport, hormone transport and/or scavenging, matrix metalloproteinase inhibition.
A genuine function of clusterin has not been defined. One tempting hypothesis says that clusterin is an extracellular chaperone protecting cells from stress induced insults caused by degraded and misfolded protein precipitates.
Clusterin is up- or down regulated on the mRNA or protein level in many pathological and clinically relevant situations including cancer, organ regeneration, infection, Alzheimer disease, retinitis pigmentosa, myocardial infarction, renal tubular damage, autoimmunity and others.