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NKp30 is a natural cytotoxicity receptor (NCR) that may assist NK cells in the lysis of tumor cells. NKp30 interacts with CD3-zeta (CD247), a T-cell receptor. A single nucleotide polymorphism in the 5'' untranslated region of the NKp30 gene has been linked to mild malaria susceptibility.

Chemokine (C-X-C motif) ligand 3 (CXCL3) is a small cytokine belonging to the CXC chemokine family that is also known as GRO3 oncogene (GRO3), GRO protein gamma (GROg) and macrophage inflammatory protein-2-beta (MIP2b). CXCL3 controls migration and adhesion of monocytes and mediates it effects on its target cell by interacting with a cell surface chemokine receptor called CXCR2. The gene for CXCL3 is located on chromosome 4 in a cluster of other CXC chemokines.

TSSK2 is a testis-specific serine/threonine-protein kinase required during spermatid development which phosphorylates TSKS at 'Ser-288' and SPAG16. TSSK2 takes part in the late stages of spermatogenesis, during the reconstruction of the cytoplasm. During spermatogenesis, TSSK2 is necessary for the transformation of a ring-shaped structure around the base of the flagellum originating from the chromatoid body.

UMP-CMP kinase and deoxycytidylate kinase (CMPK1) is an enzyme which catalyzes the phosphoryl transfer from ATP to UMP, CMP and dCMP. This enzymatic reaction brings about the formation of ADP and the corresponding nucleoside diphosphate that are necessary for cellular nucleic acid synthesis. In addition, CMPK1 has a significant role in the activation of pyrimidine analogs, which are clinically useful anti-cancer and anti-viral drugs.

ARL1 is part of the ARL (ADP-ribosylation factor-like) family of proteins, which are structurally associated to ADP-ribosylation factors (ARFs). ARFs, described as activators of cholera toxin (CT) ADP-ribosyltransferase activity, control intracellular vesicular membrane trafficking, and stimulate a phospholipase D (PLD) isoform.
ARL1 is a weak stimulator of PLD and CT in a phospholipid dependent manner.
ARL1 is a GTP-binding protein that has low efficiency as allosteric activator of the cholera toxin catalytic subunit, an ADP-ribosyltransferase. ARL1 is involved in the Golgi apparatus.

LIN28 plays an important role as a 'translational enhancer', leading specific mRNAs to polysomes and therefore increasing the competence of protein synthesis. LIN28 is a marker of undifferentiated human embryonic stem cells and it enhances the efficiency of the formation of induced pluripotent stem (iPS) cells from human fibroblasts. LIN28 binds to the let-7 pre-miRNA and blocks production of the mature let-7 microRNA in mouse embryonic stem cells. Overexpression of LIN28 is associated with human germ-cell tumors.

Homeodomain-only protein (HOPX) functions via its interaction with SRF, thus modulating the expression of SRF-dependent cardiac-specific genes and cardiac development. HOPX inhibits SRF-dependent transcription either by hindering SRF binding to DNA or by engaging histone deacetylase (HDAC) proteins which prevent transcription by SRF. HOPX is a homeodomain protein which lacks certain conserved residues required for DNA binding. HOPX overexpression causes cardiac hypertrophy.

S100G (calbindin D9K) is a vitamin D-dependent calcium-binding protein. S100G, which is a cytosolic protein, is a member of a family of calcium-binding proteins that includes calmodulin, parvalbumin, troponin C, and S100 protein. In the intestine, S100G is vitamin D-dependent and its expression correlates with calcium transport activity. S100G may increase Ca2+ absorption by buffering Ca2+ in the cytoplasm and increase ATP-dependent Ca2+ transport in duodenal basolateral membrane vesicles.

Chemokine (C-X-C motif) ligand 2 (CXCL2) is a small cytokine belonging to the CXC chemokine family that is also called macrophage inflammatory protein 2-alpha (MIP2-alpha), Growth-regulated protein beta (Gro-beta) and Gro oncogene-2 (Gro-2). CXCL2 is 90% identical in amino acid sequence as a related chemokine, CXCL1. This chemokine is secreted by monocytes and macrophages and is chemotactic for polymorphonuclear leukocytes and hematopoietic stem cells. The gene for CXCL2 is located on human chromosome 4 in a cluster of other CXC chemokines. CXCL2 mobilizes cells by interacting with a cell surface chemokine receptor called CXCR2.

ULBP2 is a member of the MHC class I family. ULBP2 is ligand for the NKG2D receptor, composed with at least ULBP1 and ULBP3. ULBPs promote multiple signaling pathways in primary NK cells, triggering the production of cytokines and chemokines. Binding of ULBPs ligands to NKG2D encourages calcium mobilization and activation of the JAK2, STAT5, ERK and PI3K kinase/Akt signal transduction pathway. In CMV infected cells, ULBP2 cooperates with soluble CMV glycoprotein UL16. This cooperation is blocked with the NKG2D receptor, providing a mechanism in which CMV infected cells can escape the immune system. Additionally, UL16 causes ULBP2 to be held in the ER and cis-Golgi apparatus so that it does not reach the cell surface.

Myosin Binding Protein C, Cardiac (MYBPC3) is the cardiac isoform of myosin-binding protein C expressed exclusively in heart muscle. Myosin-binding protein C is a myosin-associated protein found in the cross-bridge-bearing zone (C region) of A bands in striated muscle. Regulatory phosphorylation of the cardiac isoform in vivo by cAMP-dependent protein kinase upon adrenergic stimulation may be associated with modulation of cardiac contraction. MYBPC3 gene mutations are one of the causes of familial hypertrophic cardiomyopathy. In vitro MYBPC3 binds MHC, F-actin and native thin filaments, and modifies the activity of actin-activated myosin ATPase. MYBPC3 may modulate muscle contraction or it may have a more structural role.

Nectin-1, also referred to as ED4, is a poliovirus receptor- related 1 protein is a part of the Nectin family. Nectin-1 endorses cell-cell contacts by forming homophilic or heterophilic trans-dimers. Heterophilic interactions among PVRL1/nectin-1 & PVRL4/nectin-4 and among PVRL1/nectin-1 & PVRL3/nectin-3 have been found. Nectin-1 acts as an entry receptor for herpes simplex virus & pseudorabies virus as well. Likewise, Neurite outgrowth-promoting activity has been shown by Nectin-1.

Lymphokine-activated killer T-cell-originated protein kinase (PBK) is a serine/threonine kinase related to the dual specific mitogen-activated protein kinase (MAPKK) family. PBK is abundant in placenta (is also found in the testis’ outer cell layer of seminiferous tubules) and absent from adult brain tissue. PBK is involved in the activation of lymphoid cells and supports testicular functions, with a possible role in the process of spermatogenesis. Mitotic phosphorylation is required for PBK’s catalytic activity. Once phosphorylated,PBK forms a complex with TP53, leading to TP53 destabilization and weakening of G2/M checkpoint during some kind of DNA damage. PBK is active only during mitosis. In addition, a PDZ domain in the tumor suppressor protein Dlg can coordinate with the T/SXV motif of PBK. PBK also phosphorylates MAP kinase p38, and may have a role in the activation of lymphoid cells.

The acute phase plasma protein ORM1 synthesized by the liver mediates the interaction between blood cells and endothelial cells. In addition, together with haptoglobin and C reactive protein, ORM1 regulates the extravasation of the cells through infection and inflammation. Expression of ORM1 is induced by acute-phase stimulatory mediators such as bacterial lipopolysaccharides.

LIN7B (VELI2), is a member of the Velis family. Velis family contains minor synaptic proteins which interact with other proteins at the post-synaptic density (PSD) of neuronal synapses. Velis which contain the PDZ motif, participate in recruiting cell adhesion molecules, receptors, and channels. Lin7B protein is ubiquitously expressed with a high expression in the brain, liver, and testis. Lin7B localizes at the synaptic junctions in neurons, bind to CASK, which is a neurexin-binding protein highly concentrated in synapses, and Mint1, a binding partner with a vesicle trafficking protein.

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is widely used in molecular biology through its unique high affinity for the vitamin biotin. The dissociation constant (Kd) of the biotin-streptavidin complex is about ~10-15 mol/L. The strong affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. The streptavidin/biotin system has one of the biggest free energies of association of yet observed for noncovalent binding of a protein and small ligand in aqueous solution (K_assoc = 10**14). The complexes are also extremely stable over a wide range of temperature and pH.

Complement C5 is cleaved into C5a and C5b and is activated by all 3 pathways of complement activation. Each pathway of complement activation generates proteolytic enzyme complexes which binds to the target surface. These enzymes cleave a peptide bond in the larger alpha chain of C5 releasing the highly potent anaphylatoxin C5a and activating C5b. C5a has an imperative role in chemotaxis and C5b forms the 1st part of the complement membrane attack complex. Complement C5 is the 5th component of complement, which plays a central role in inflammatory and cell killing processes.

Colipase (CLPS) is a protein co-enzyme essential for optimal enzyme activity of pancreatic lipase. CLPS is secreted by the pancreas as an inactive form, procolipase, which is then activated in the intestinal lumen by trypsin. CLPS prevents the inhibitory effect of bile salts on the lipase-catalyzed intraduodenal hydrolysis of dietary long-chain triglycerides. CLPS allows lipase to anchor noncovalently to the surface of lipid micelles, counteracting the destabilizing influence of intestinal bile salts. CLPS binds to the C-terminal, non-catalytic domain of lipase, thus stabilizing an active conformation and significantly increasing the whole hydrophobic binding site.

Myosin regulatory light chains, including MRCL3, MYLPF and MYL9, regulate contraction in smooth muscle and non-muscle cells via phosphorylation by MLCK (myosin light chain kinase). Phosphorylation of myosin regulatory light chains, catalyzed by MLCK in the presence of calcium and calmodulin, increases the actin-activated myosin ATPase activity, thus regulating the contractile activity. MYLPF is vital for fast and slow skeletal muscle development.

Connective Tissue Growth Factor belongs to the CCN family of proteins. The CCN family presently consists of six members in human also known as: Cyr61 (Cystein rich 61), CTGF (Connective Tissue Growth Factor), Nov (Nephroblastoma Overexpressed gene), WISP-1, 2 and 3 (Wnt-1 Induced Secreted Proteins). The CCN genes encode secreted proteins associated with the Extracellular Matrix (ECM) and cell membrane. CCN proteins are matricellular proteins which are involved in the regulation of various cellular functions including: proliferation, differentiation, survival, adhesion and migration. They are expressed in derivatives of the three embryonic sheets and are implicated in the development of kidney, nervous system, muscle, bone marrow, cartilage and bone. During adulthood, they are implicated in wound healing, bone fracture repair, and pathologies such as: fibrosis, vascular ailments and tumorigenesis.
Full length secreted CCN proteins can show an antiproliferative activity, whereas truncated isoforms are likely to stimulate proliferation and behave as oncogenes. The full length protein consists of four modulesModule I shares partial identity with the N-terminal part of the Insulin-like Growth Factor Binding Proteins (IGFBPs).
Module II includes a stretch of 70amino acid residues – which shares sequence identity with the Von Willebrand Factor Type C repeat (VWC).
Module III contains sequences sharing identity with the Thrombospondin type 1 repeat (TSP1) (WSXCSXXCG), which is thought to be implicated in the binding of sulfated glycoconjugates and to be important for cell adhesion. Module IV, also designated CT, is encoded by exon5. It is the leasts conserved one of the four domains at the level of nucleotide sequence, but it appears to be critical for several of the biological functions attributed to the CCN proteins. Module IV resembles the CT domain of several extracellular protein including, Von Willebrand's factor and mucins. Sequence similarities to heparin-binding motifs are also found within this domain. Proteolysis of the secreted full-length CCN proteins that has been reported in the case of CCN2 and CCN3 might result in the production of CCN-derived peptides with high affinity for ligands that full-length CNN proteins bind only poorly. Amino-truncated CCN2 isoforms were biologically active whereas no specific biological activity has been attributed to the truncated CCN3. Although the molecular processes underlying the production of these secreted isoforms is presently unknown, it is important to note that proteolysis occur at the same amino acid residues in both CCN2 and CCN3. An elevated expression of CCN2 has also been detected by Northern blotting in human invasive mammary ductal carcinomas, dermatofibromas, pyogenic granuloma, endothelial cells of angiolipomas and angioleiomyomas, and in pancreatic tumors. A study performed with chondrosarcomas representative of various histological grades established that CCN2 expression was closely correlated with increasing levels of malignancy. In agreement with CCN2 playing a role in brain tumor angiogenesis, immunocytochemistry studies indicated that both glioblastoma tumor cells and proliferating endothelial cells stained positive for CCN2. In astrocytomas, CCN2 expression was particularly elevated in high grade tumors, with a marked effect of CCN2 on cell proliferation. Downregulation of CCN2 expression in these cells was associated with a growth arrest at the G1/S transition while over-expression of CCN2 induced a two-fold increase of the number of cells in the G1 phase. Gene profiling analysis allowed to identify a set of about 50 genes whose expression might account for the proliferative activity of CCN2 in these cells.
CCN2 was seen in a higher proportion of mononuclear cells of patients with acute lymphoblastic leukemia.

Ras-related protein Rap-2b (RAP2B) is a part of RAS-related genes family. RAP2B has a threonine residue at aa 61Unlike normal ras proteins which have a nontransforming glutamine residue at that position. The threonine residue makes the intrinsic GTPase activity for Rap2B lower, by this means allows RAP2B to exist in the activated state for a longer period of time than normal ras proteins. RAP2B is a platelet protein which is activated by thrombin and involved in platelet activation. RAP2B may be a candidate oncogene which takes part in carcinogenesis through activation of NF-kappaB pathway.

Rab3A is a member of the small GTPase superfamily, Rab family. Rab3A is a small, Ras-like GTPase expressed in neuroendocrine cells, in which Rab3A is linked with secretory vesicle membranes and regulates exocytosis. Rab3A protein may have a role in neurotransmitter release by regulating membrane flow in the nerve terminal.