Search results

VAPB Vesicle-associated membrane protein (VAMP)-associated protein B (aka VAPB) is a type IV transmembrane protein and belongs to the VAP family of proteins. VAPB may have a role in vesicle trafficking. VAPB is found in plasma and intracellular vesicle membranes as a homodimer and heterodimer with VAPA, and interacts with VAMP1 and VAMP2. VAPB defects are the basis for the amyotrophic lateral sclerosis type 8 and spinal muscular atrophy autosomal dominant Finkel type.

TAGLN is a transformation and form-change responsive actin cross-linking/gelling protein that is part of the calponin family. TAGLN is expressed abundantly in fibroblasts and smooth muscle. TAGLN participates in calcium interactions and contractile properties of the cell that contribute to replicative senescence. Throughout embryogenesis, TAGLN is expressed in smooth, cardiac and skeletal muscle, but is limited during late fetal growth and adulthood to all vascular and visceral smooth muscle cells and low levels of expression in heart. TAGLN is downregulated in several transformed cell lines, showing that a decrease of TAGLN expression is an premature indicator of the onset of transformation.

Troponin is a fundamental regulatory protein of striated muscle contraction, and together with tropomyosin, is positioned on the actin filament. Troponin has 3 subunits: TnI- the inhibitor of actomyosin ATPase; TnT- contains the binding site for tropomyosin; and TnC- the protein encoded by the TNNC1 gene. The binding of calcium to TnC stops the inhibitory action of TnI, consequently allowing the interaction of actin with myosin, the hydrolysis of ATP, and the generation of tension. Mutations in the TNNC1 gene are linked to cardiomyopathy dilated type 1Z.

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%.

Complement Component C5a (C5a) is involved in the complement system and it is encoded by the C5 gene in human. Complement C5 is cleaved into C5a and 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. C5a protein is composed of alpha and beta polypeptide chains, which are linked by a disulfide bridge. An activation peptide, C5a, which is an anaphylatoxin, which has potent spasmogenic and chemotactic activity, is derivative from the alpha polypeptide via cleavage with a convertase. The C5b macromolecular cleavage product forms a complex with the C6 complement component, and this complex is the basis for creation of the membrane attack complex, which includes supplementary complement components.

Muted homolog (MUTED) is a component of the BLOC-1 complex, a complex which is necessary for normal biogenesis of lysosome-related organelles (LRO), such as platelet dense granules and melanosomes. The BLOC-1 complex is needed to steer membrane protein cargos into vesicles assembled at cell bodies for release into neurites and nerve terminals. In addition, this complex, along with SNARE proteins, is suggested to be involved in neurite extension. MUTED also interacts with pallidin, dystrobrevin binding protein 1 and CNO/cappuccino. MUTED is ubiquitously expressed with higher levels in the brain, bone marrow, kidney, and liver and lower levels in the skeletal muscle.

HUS1 is a component of an evolutionarily conserved, genotoxin-activated checkpoint complex. HUS1 protein connects with Rad9 and Rad1 to form the 9-1-1(RAD9-RAD1-HUS1) complex, that confines to DNA lesions and promotes DNA damage signaling and repair or apoptosis, cell cycle arrest. The trimeric complex is structurally similar to the proliferating cell nuclear antigen (PCNA) sliding clamp and interacts with Rad17 as a clamp-clamp loader pair during the DNA damage response.

Activins are homodimers or heterodimers of the different β subunit isoforms, part of the TGFβ family. Mature Activin A has two 116 amino acids residues βA subunits (βA-βA). Activin displays an extensive variety of biological activities, including mesoderm induction, neural cell differentiation, bone remodelling, haematopoiesis, and reproductive physiology. Activins takes part in the production and regulation of hormones such as FSH, LH, GnRH and ACTH. Cells that are identified to express Activin A include fibroblasts, endothelial cells, hepatocytes, vascular smooth muscle cells, macrophages, keratinocytes, osteoclasts, bone marrow monocytes, prostatic epithelium, neurons, chondrocytes, osteoblasts, Leydig cells, Sertoli cells, and ovarian granulosa cells.

Signal-Regulatory Protein Gamma (SIRPG) belongs to the signal-regulatory protein (SIRP) family whose members are receptor-type transmembrane glycoproteins which negatively regulate the receptor tyrosine kinase-coupled signaling processes. SIRPG is also a part of the immunoglobulin superfamily.

C4b is derived from native C4 upon cleavage and release of C4a. 4b is created by cleavage of purified C4 with the classical pathway activated protease C1s enzyme. C4b is essential to the function of 2 of the 3 pathways of complement. Both the classical and lectin pathways of complement activation generate surface-bound active proteases that cleave C4. These enzymes cleave a peptide bond in C4 releasing the anaphylatoxin C4a and activating C4b. C4A and C4B are 2 variants of C4 that are common in man whereas, in animals who have only 1 type usually have C4B.

A 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.

Sex-hormone-binding globulin (SHBG) is a beta-globulin which specifically binds steroid hormones; it is involved in the transport of sex steroids in plasma. The main site of SHBG synthesis is assumed to be the hepatocytes. The production of SHBG is regulated by androgen/estrogen balance, thyroid hormones, and dietary factors, among others. The concentration of SHBG is a key factor regulating their distribution between protein-bound and free states. SHBG concentration determination is primarily significant in the evaluation of mild disorders of androgen metabolism and it allows detection of women with hirsutism who are likely to react to estrogen therapy. Testosterone/SHBG-ratios correlate well with both measured and calculated values for free testosterone thus aid to distinguish between subjects with excessive androgen activity and normal individuals. SHBG gene polymorphisms are linked with polycystic ovary syndrome and type 2 diabetes mellitus.

Glypican-3 (GPC3) belongs to the glypican family, and is highly expressed in the lung, liver, and the kidney. In some tissues, GPC3 functionss as a tumor suppressor gene and an oncofetal protein. The Glypican-3 protein is currently considered as a tumor marker and potential target for immunotherapy. Glypican-3 binds to and inhibits the dipeptidyl peptidase activity of CD26, and it can also induce apoptosis in certain cell types. Deletion mutations in the GPC3 gene are linked with Simpson-Golabi-Behmel syndrome, aka Simpson dysmorphia syndrome.

Otubain 1 (OTUB1) belongs to the ovarian tumor (OUT) superfamily of predicted cysteine proteases and inhibits cytokine gene transcription in the immune system through its interaction with a ubiquitin protease and E3 ubiquitin ligase. OTUB1 is a highly specific ubiquitin iso-peptidase, it cleaves ubiquitin from branched poly-ubiquitin chains but not from ubiquitinated substrates. OTUB1 is believed to work in specific ubiquitin-dependent pathways, possibly by providing an editing function of polyubiquitin chain growth. OTUB1 is a hydrolase that removes conjugated ubiquitin from proteins in vitro and may therefore have a significant regulatory role in the level of protein turnover by preventing degradation. Additionally, OTUB1 is a regulator of T-cell anergy, a phenomenon that occurs when T-cells are rendered impassive to antigen re-challenge and no longer respond to their cognate antigen. OTUB1 acts via its interaction with RNF128/GRAIL, which is an essential inductor of CD4 T-cell anergy.

WIF1 binds to wnt proteins and inhibits their activities. WIF1 plays a role in mesoderm segmentation. WNT proteins are extracellular signaling molecules that take part in the control of embryonic development & cancer. WIF1 protein contains a WNT inhibitory factor (WIF) domain and 5 epidermal growth factor (EGF)-like domains. WIF1 takes part in mesoderm segmentation. WIF1 protein is found to be present in fish, amphibia and mammals. WIF1 is a recurrent target in human salivary gland oncogenesis. Downregulation of WIF1 takes part in the development and progression of pleomorphic adenomas. WIF1 is a tumor suppressor, specifically in nonfunctioning pituitary tumors.

Autophagy Related 3 (ATG3) is a conjugating enzyme essential for the cytoplasm to vacuole transport (Cvt), autophagy, and mitochondrial homeostasis. ATG3 is localizes to the cytoplasm and is expressed in tissues with predominant levels found in kidney, placenta, liver, heart and skeletal muscle. ATG3 catalyzes a reaction which is necessary for autophagy. That reaction is the formation of the Atg8-phosphatidylethanolamine (ATG-PE) conjugate.

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.

LAMTOR2 is a member of the GAMAD family. LAMTOR2 is highly conserved with a mouse protein linked with the cytoplasmic face of late endosomes and lysosomes. The mouse protein interacts with MAPK scaffold protein 1, which is a component of the mitogen-activated protein kinase pathway. LAMTOR2 gene mutation has been associated with a primary immunodeficiency syndrome in humans, proposing a role for this protein in endosomal biogenesis.

Cartilage-associated protein (CRTAP) is a secreted protein localizing to the extracellular space which takes part in collagen post-translational modifications, extracellular fibril assembly and intracellular trafficking. CRTAP which is mainly expressed with predominant expression in articular chondrocytes is essential for efficient 3-hydroxylation of fibrillar collagen prolyl residues. Mutations in the gene encoding CRTAP might cause to autosomal recessive osteogenesis imperfecta (OI) type 7 and type 2B.

Vascular endothelial growth factor is an important signaling protein involved in both angiogenesis and vasculogenesis.VEGF activity has been mostly studied on cells of the vascular endothelium, although it does have effects on a number of other cell types (e.g. stimulation monocyte/macrophage migration, neurons, cancer cells, kidney epithelial cells ).VEGF mediates increased vascular permeability, induces angiogenesis, vasculogenesis and endothelial cell growth, promotes cell migration, and inhibits apoptosis. In vitro, VEGF has been shown to stimulate endothelial cell mitogenesis and cell migration. VEGF is also a vasodilator and increases microvascular permeability and was originally referred to as vascular permeability factor.
Elevated levels of VEGF is linked to POEMS syndrome, also known as Crow-Fukase syndrome. Mutations in VEGF have been associated with proliferative and nonproliferative diabetic retinopathy.

TNFSF15 is a cytokine that belongs to the tumor necrosis factor (TNF) ligand family. This protein is abundantly expressed in endothelial cells, but is not expressed in either B or T cells. The expression of TNFSF15 is inducible by TNF and IL-1 alpha. This cytokine is a ligand for receptor TNFRSF25 and decoy receptor TNFRSF21/DR6. It can activate NF-kappaB and MAP kinases, and acts as an autocrine factor to induce apoptosis in endothelial cells. TNFSF15 is also found to inhibit endothelial cell proliferation, and thus may function as an angiogenesis inhibitor. An additional isoform encoded by an alternatively spliced transcript variant has been reported but the sequence of this transcript has not been determined.