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Frataxin is a mitochondrial iron binding protein that is part of the FRATAXIN family. Frataxin functions in regulating mitochondrial iron transport and respiration. The expansion of intronic trinucleotide repeat GAA results in Friedreich ataxia. Frataxin plays a role in iron homeostasis. Frataxin is an anti-apoptotic protein which prevents mitochondrial damage and reactive oxygen species (ROS) production.

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.

SRP54 is a 54-kDa subunit of the signal recognition particle (SRP), a cytoplasmic ribonucleoprotein complex which leads the translocation of newly synthesized secretory proteins from the polysome to the endoplasmic reticulum. SRP is composed of six polypeptides and a tRNA-like molecule known as 7SL RNA. SRP54 is a GTP-binding protein that directly binds the signal sequences of nascent secretory and membrane proteins. Anti-SRP autoantibodies take place in patients with an autoimmune chronic muscle inflammation called polymyositis. These auto-antibodies predominantly recognize the SRP54 subunit and in addition are able to immunoprecipitate several of the SRP subunits and the RNA component. Nearly 5% of myositis patients are positive for anti-SRP autoantibodies, increasing to 18% in the subgroup of Jo-1 autoantibody-negative patients. The classic 'anti-SRP syndrome' is a severe form of polymyositis in which the myositic inflammation is acute and aggressive onset, with common myalgias and cardiac involvement. Normally there is a poor reaction to therapy with a 5-year survival rate of about 25%.

cAMP-dependent protein kinase inhibitor beta (PKIB) belongs to the cAMP-dependent protein kinase inhibitor family. PKIB may interact with the catalytic subunit of cAMP-dependent protein kinase and function as a competitive inhibitor.

PINK1 is a serine/threonine protein kinase which is found in the mitochondria. PINK1 shields cells from stress-induced mitochondrial dysfunction. Mutations results in one form of autosomal recessive early-onset Parkinson disease.

Prolactin-inducible protein (PIP) is a main protein component of benign breast gross cysts. PIP is a famous indicator of breast cancer, since it is found in around 50% of all breast cancer specimens. PIP is expressed in exocrine glands, in pathologic conditions, in breast cysts and breast cancers exhibiting apocrine features. PIP and prostate specific antigen are co-expressed in androgen receptor-positive breast tumours.

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.

Family with Sequence Similarity 107, Member B (FAM107B) which is a part of the FAM107 family, is expressed in most tissues in the human body. FAM107B exists in all stages of human development.

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.

SRP14 is a ribonucleoprotein complex which mediates the directing of proteins to the endoplasmic reticulum. The “Alu domain” of SRP is comprised of the heterodimer of the SRP9 and SRP14 proteins that are bound to the 5' and 3' terminal sequences of SRP RNA. SRP9/14 binding may be critical to the transcription, maturation, nucleolus localization and transport of SRP RNA.

STE20-Related Kinase Adaptor Alpha (STRADA) is a part of the STE- 20 like kinase family which stimulates MAPK pathways by activating MAPKKK. STRADA is an upstream activator of LKB1 and also leads the sub-cellular localization of LKB1 by fixing it in the cytoplasm. The interaction between STRADA-LKB1 leads to phosphorylation of STRADA and enhanced autophosphorylation of LKB1.

Capping Protein (Actin Filament) Muscle Z-Line, Alpha 2 also known as CAPZA2 belongs the F-actin capping protein alpha subunit family. It is the alpha subunit of the barbed-end actin binding protein Cap Z. By capping the barbed end of actin filaments, Cap Z regulates the growth of the actin filaments at the barbed end. Among the diseases associated with CAPZA2 are endocarditis, and cervicitis.

SKP is a 17kDa trimeric periplasmic chaperone that supports outer membrane proteins in their folding and insertion into membranes. SKP protein is necessary for the normal release of ompA from the inner membrane, the maintenance of its solubility in the periplasm, and, in association with lipopolysaccharide (LPS), for the efficient folding and insertion of ompA into the outer membrane.

a-Synuclein (amino acids 1-140), an acidic neuronal protein of 140 amino acids, is extremely heat-resistant and is natively unfolded with an extended structure primarily composed of random coils. a-synuclein has been suggested to be implicated in the pathogenesis of Parkinson’s disease and related neurodegenerative disorders, and more recently, to be an important regulatory component of vesicular transport in neuronal cells. Moreover, recent studies have shown that a-synuclein has chaperone activity and that this activity is lost upon removing its C-terminal acidic tail (amino acids 96-140).

Hyaluronan And Proteoglycan Link Protein 1, which is also known as HAPLN1 is a part of the HAPLN family.HAPLN1 contains one Ig-like V-type domain and two Link domains. In the extracellular cartilage matrix, HAPLN1 stabilizes the aggregates of proteoglycan monomers by means of hyaluronic acid .

Signal-Regulatory Protein Alpha, SIRPA belongs to the signal-regulatory-protein (SIRP) family, as well as theimmunoglobulin super family. The members of the SIRP family are receptor-type transmembrane glycoproteins which areinvolved in the negative regulation of receptor tyrosine kinase-coupled signaling processes. SIRPA can bephosphorylated by tyrosine kinases. The phospho-tyrosine residues of this PTP have been shown to recruit SH2domain containing tyrosine phosphatases (PTP), and perform as substrates of PTPs. SIRPA take part insignal transduction mediated by a variety of growth factor receptors. CD47 has been shown to be a ligand forSIRPA.

SCP2 sterol-binding domain containing 1 also known as SCP2D1 contains 1 SCP2 domain. One of the diseases associated with SCP2D1 is d-bifunctional protein deficiency.

Speckle-type POZ protein (SPOP) belongs to the Tdpoz family containing one N-terminal MATH (Meprin and TRAF homology) domain and one C-terminal BTB/POZ domain. SPOP inhibits IPF1/PDX1 transactivation of established target promoters, may be by recruiting a repressor complex. SPOP is involved in ubiquitinylation and protein degradation as a result of an interaction with CUL-3.

SERPINH1 is part of the serpin superfamily of serine proteinase inhibitors. SEPINH1 expression is induced by heat shock. HSP47 localizes to the endoplasmic reticulum lumen and binds collagen therefore it is a molecular chaperone which takes part in the maturation of collagen molecules, facilitating the folding and assembly of procollagen molecules, retaining unfolded molecules within the ER, and assisting the transport of correctly folded-molecules from the ER to Golgi apparatus. Autoantibodies to HSP47 protein have been found in rheumatoid arthritis. SERPINH1 binds specifically to collagen and acts as a chaperone in the biosynthetic pathway of collagen.

Sprouty Homolog 4 (SPRY4) is an inhibitor of the receptor-transduced mitogen-activated protein kinase (MAPK) signaling pathway. SPRY4 is positioned upstream of RAS activation. SPRY4 protein functions include suppressing the EGFR-transduced MAPK signaling pathway as well as impairing the formation of GTP-Ras.

Intracisternal A particle-promoted polypeptide (IPP) is a 66kDa protein (584 amino acids), which contains an N-terminal POZ protein-protein interaction domain and a C-terminal kelch repeat domain consisting of six tandem arranged repeats. The POZ domain (also called BTB domain) is present near the N-terminus of a fraction of zinc finger proteins and in protein that contain the pfam01344 motif such as kelch and pox virus proteins. The BTB/POZ domain mediates homomeric dimerization and in some instances heteromeric dimerization. POZ domains from several zinc finger proteins have been shown to mediate transcriptional repression and to interact with components of histone deacetylase co-repressor complexes including N-coR and SMRT.

The PARK7 is a ubiquitously expressed protein involved in various cellular processes including spermatogenesis and fertilization, cancer, RNA-binding, androgen-receptor signaling and oxidative stress. Mutations in the PARK7 are the cause of autosomal recessive early-onset Parkinson’s disease 7 (Park7).

Impact RWD Domain Protein (IMPACT) is a member of the IMPACT family which is comprised of 1 RWD domain. IMPACT is a translational regulator which certifies constant high levels of translation under amino acid starvation. IMPACT interacts with GCN1/GCN1L1, thus preventing activation of GCN2 protein kinases (EIF2AK1 to 4) and subsequent down-regulation of protein synthesis. IMPACT is highly expressed especially in brain.