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Charged multivesicular body protein 6 (CHMP6) is a member of the SNF7 family. The CHMP6 protein is a core component of the endosomal sorting necessary for transport complex III (ESCRT-III) that is involved in multivesicular bodies (MVBs) formation and sorting of endosomal cargo proteins into MVBs. MVBs contain intraluminal vesicles (ILVs) which are produced by invagination and scission from the limiting membrane of the endosome and generally are transported to lysosomes facilitating degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids.

Charged multivesicular body protein 1b (CHMP1B) is a member of the chromatin-modifying protein/charged multivesicular body protein (CHMP) family. CHMP1B is a possible peripherally associated component of the ESCRT-III (endosomal sorting required for transport complex III) which is involved in MVBs (multivesicular bodies) formation and sorting of endosomal cargo proteins into MVBs. The MVBs contain ILVs (intraluminal vesicles) which are created by invagination and scission from the limiting membrane of the endosome and generally are transported to lysosomes enabling degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids.

Charged multivesicular body protein 1a (CHMP1A) is a member of the vacuolar sorting protein family and functions as chromatin-modifying protein. These complexes are essential for sorting endosomal articles into multivesicular bodies (MVBs), as well as vital for the formation of these bodies. The MVBs pathway mediates distribution of transmembrane proteins into the lumen of the lysosome for degradation. CHMP1 interacts with VPS4B and localizes to early endosomes.

Charged Multivesicular Body Protein 5 (CHMP5) is a member of the chromatin-modifying protein/charged multivesicular body protein (CHMP) family. These proteins comprise the ESCRT-III (endosomal sorting complex required for transport III), a complex involved in degradation of surface receptor proteins and development of endocytic multivesicular bodies (MVBs). Certain CHMPs have both nuclear and cytoplasmic/vesicular distributions, and one such CHMP the CHMP1A, is essential for both MVB formation and regulation of cell cycle progression.

Charged multivesicular body protein 3 (VPS24/CHMP3) is a member of the vacuolar sorting protein family and function as chromatin modifying proteins. VPS24 links directly with CHMP2 and CHMP4 for the disassembly of ESCRT-III complex in an ATP-dependent manner. During HIV-1 infection, the virus uses the ESCRT-III complex to mediate budding and exocytosis of viral proteins. VPS24 overexpression strongly hinders HIV-1 release.

Chromatin modifying protein 2A (CHMP2A) is a member of the SNF7 family and it is a component of the ESCRT III complex, which is required for MVBs (multivesicular bodies) formation and sorting of endosomal cargo proteins into MVBs.
The MVB pathway mediates release of transmembrane proteins into the lumen of the lysosome for degradation. The MVB pathway requires the sequential function of ESCRT-O, -I,-II and -III complexes. ESCRT-III proteins generally detach from the invaginating membrane before the ILV (intraluminal vesicles) is released. ESCRT-III proteins are thought to mediate the basic vesicle extrusion and/or membrane fission activities, probably in conjunction with the AAA ATPase VPS4.

CHMP4A is a member of the SNF7 family and operates as chromatin-modifying protein. CHMP4A is a key component of the endosomal sorting vital for transport complex III (ESCRT-III) which takes part in multivesicular bodies (MVBs) formation and sorting of endosomal cargo proteins into MVBs. Additionally, during HIV-1 infection, the virus utilizes the ESCRT-III complex to facilitate budding and exocytosis of viral proteins through the connection of CHMP4 and a protein engaged by HIV-1 p6, which exists in viral Gag assembly and budding. CHMP4A is expressed in higher quantities in skeletal muscle, kidney, liver and heart.

The recombinant Protein A/G is a genetically engineered protein comprised of 7 IgG-binding domains EDABC-C1C3, corresponding to the Protein A and G domains which are included in the recombinant sequence. The Protein A part is from Staphylococcus aureus segments E, D, A, B and C. The Protein G part is from Streptococcus segments C1 and C3. The recombinant Protein A/G has a broader binding capacity than either Protein A or Protein G alone. The recombinant Protein A/G is ideal for purification of monoclonal or polyclonal IgG antibodies. Protein A/G binds to various human, mouse and rat IgG subclasses such as the human IgG1, IgG2, IgG3, IgG4; mouse IgG2a, IgG2b, IgG3 and rat IgG2a, IgG2c. In addition, Protein A/G binds to total IgG from cow, goat, sheep, horse, rabbit, guinea pig, pig, dog and cat.

MAP1LC3B is a member of the MAP1 LC3 family. MAP1LC3B is a subunit of neuronal microtubule-associated MAP1A and MAP1B proteins, that are involved in microtubule assembly and important for neurogenesis. In addition, MAP1LC3B takes part in formation of autophagosomal vacuoles and is expressed mainly in heart, testis, brain and skeletal muscle.

Protein A is a cell wall component produced by several strains of Staphylococcus aureus. The recombinant Protein A is genetically engineered protein and holds 5 IgG-binding regions of protein A. Recombinant Protein A functions basically the same as native Protein A and is perfect for purification of polyclonal or monoclonal IgG antibodies. Protein A binds to human IgG1, IgG2 and IgG4, mouse IgG2a, IgG2b and IgG3 and rat IgG2c. Protein A also binds to total IgG from rabbit, pig, dog, cat, and guinea pig.

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.

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.

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.

Tubby-related protein 1 (TULP1) belongs to the TULP family of 4 proteins (TUB and TULP1, -2, and -3), categorized structurally by the highly conserved C-terminal half of the protein. Tubby-like gene family (TULPs) members are found in plants, vertebrates, and invertebrates and encode proteins of unknown function. TULP proteins share a conserved C-terminal region of roughly 200 amino acid residues. In the retina, TULP1 is observed exclusively in the photoreceptor cells, localizing predominantly in the inner segments and connecting cilium and to a lesser degree in the perinuclear cytoplasm and synaptic termini. TULP1 gene mutations are linked with retinitis pigmentosa.

Vacuolar protein sorting-associated protein 26A (VPS26A) is a vital element of the retromer complex, which is required to recover lysosomal enzyme receptors (IGF2R and M6PR) from endosomes to the trans-Golgi network. Furthermore, VPS26A is essential in the regulation of transcytosis of the polymeric immunoglobulin receptor (pIgR-pIgA). Expression analysis in yeast and mammalian cells reveal that VPS26A interacts directly with VPS35 that functions as the core of the retromer complex.

Protein A is a cell wall protein deriving from Staphylococcus aureus which exhibits unique binding properties for IgG from a variety of mammalian species and for some IgM and IgA as well. It binds with the Fc region of immunoglobulins through interaction with the heavy chain. It couples to a wide variety of reporter molecules including fluorescent dyes, enzyme markers, biotin, colloidal gold and radioactive iodine without affecting the antibody binding site. Recombinant Protein A was developed to increase the specificity of the molecule for IgG and is widely used both in research and bioprocessing. The recombinant protein A is produced by expressing a modified protein A gene in E.coli. A specific purification process with strict quality control was taken to get the recombinant protein A with the purity of more than 98% , no human IgG affinity step is used during validated fermentation and purification and devoid of bacterial contaminant found normally in native Protein A. (Free of Staphylococcus endotoxins and hemolysin).

Eledoisin is an undecapeptide formed in the venom gland of several species of octopuses and is used as a vasodilator and a contraction agent of extravascular smooth muscle.

SPARC, an acronym for “secreted protein, acidic and rich in cysteine”, is also known as osteonectin or BM-40. It is the founding member of a family of secreted matricellular proteins with similar domain structure. The 303 amino acid, 43 kDa protein contains a 17 aa signal sequence, an N-terminal acidic region that binds calcium, a follistatin domain containing Kazal-like sequences, and a C-terminal extracellular calcium (EC) binding domain with two EF-hand motifs. SPARC is produced by fibroblasts, capillary endothelial cells, platelets and macrophages, especially in areas of tissue morphogenesis and remodeling. SPARC shows context-specific effects, but generally inhibits adhesion, spreading and proliferation, and promotes collagen matrix formation. For endothelial cells, SPARC disrupts focal adhesions and binds and sequesters PDGF and VEGF. SPARC is abundantly expressed in bone, where it promotes osteoblast differentiation and inhibits adipogenesis.

Though the exact role of MMACHC is unknown, its C-terminal region shows similarity to TonB, which is a bacterial protein involved in energy transduction for cobalamin (vitamin B12) uptake. Therefore, it is suggested that MMACHC may have a role in the binding and intracellular trafficking of cobalamin. MMACHC mutations are linked with methylmalonic aciduria and homocystinuria type cblC. MMACHC is widely expressed, it is expressed at higher level in the fetal liver, however it is also expressed in the spleen, lymph node, thymus and bone marrow. MMACHC is weakly or not expressed in the peripheral blood leukocytes.

Alpha 1-microglobulin (A1M) is a lipocalin superfamily member (kernal lipocalins). A1M is a low molecular weight protein component of plasma. A1M is distributed in plasma and extravascular compartments of all organs. Alpha-1 Microglobulin is found in mammals, birds, amphibians and fish. The primary sites of A1M synthesis are the liver and the kidney. Around the opening of the lipocalin pocket three lysyl residues are situated; those residues carry yellow-brown modification derived from the binding and degradation of heme and kynurenin (a tryptophan metabolite). A1-Microglobulin’s reductase and dehydrogenase have broad biological substrate specificity properties due to its’ free cysteine side-chain which is located in a flexible loop. Alpha-1-microglobulin is glycosylated by three separate carbohydrate chains: two complex carbohydrates which are N-linked to asparagines at residues 17 and 96, and the other simple carbohydrate which is O-linked to threonine at position 5. The carbohydrates comprise 22% of the total molecular mass of the protein. The glycosylation varies between species.
A1M exists in two forms- a free form and complexed to other macromolecules: in humans- complexed to immunoglobulin A (IgA), in rat- complexed to alpha-1-inhibitor-3. Free A1M is exceptionally heterogeneous in charge (therefore also known as protein HC), and is found tightly linked to a chromophore. The free Alpha-1-microglobulin is a monomeric protein composed of one 188 residue polypeptide and contains three cysteines, two of which (residues 75 and 173) form a conserved intra-molecular disulphide link. The chromophoric group is covalently bound to the free cysteine residue at position 34. A1M binds retinol as a major ligand, but this is probably distinct from its covalent chromophore.
Half of all human plasma A1M (approximately 0.03mg/ml) forms a 1:1 complex with about 5% of plasma immunoglobulin A. The resulting macromolecular complexes’ molecular weight is 200000, and a plasma concentration of 0.3mg/ml. The complex can exhibit both antibody activity and affect many of the biological actions of free Alpha-1-microglobulin.
Alpha-1-microglobulin was first discovered in pathological human urine.
It was suggested that A1M might be involved in tissue defense against reactive oxygen species, oxidation by heme and kynurenin. Evidence also suggests that A1M functions in the regulation of the immune system. Other functions include inhibition of stimulation of cultured lymphocytes by protein antigens; induction of cell division of lymphocytes, a mitogenic effect that can either be enhanced or inhibited by the action of other plasma components; inhibition of neutrophil granulocyte migration in vitro; and inhibition of chemotaxis.

PDCD1 is a cell surface membrane protein of the immunoglobulin superfamily. PDCD1 is expressed in pro-B-cells and is thought to have a role in their differentiation. In mice, expression of PDCD1 gene is induced in the thymus when anti-CD3 antibodies are injected and large numbers of thymocytes undergo apoptosis. Mice deficient for the PDCD1 gene bred on a BALB/c background developed dilated cardiomyopathy and died from congestive heart failure. These studies suggest that the PDCD1 gene product may also be important in T cell function and contribute to the prevention of autoimmune diseases.

SBDS is part of an extremely preserved protein family which exists from archaea to vertebrates and plants. SBDS protein functions in RNA metabolism and has a role in the biogenesis of the 60S ribosomal subunit and translational activation of ribosomes. Shwachman-Diamond syndrome is a rare autosomal recessive disorder produced by mutations in the SBDS gene.

SPA17 is a protein present at the cell surface. SPA17 was characterized by its participation in the binding of sperm to the zona pellucida of the oocyte. The central portion of SPA17 has carbohydrate binding motifs and likely takes part in cell-cell adhesion functions such as immune cell migration and metastasis.