Antibody database

Transforming growth factor-beta receptor III (TGF-beta RIII) is one of three receptors for the secreted growth factor TGF-beta. Unlike type I and type II TGF-beta receptors, TGF-beta RIII does not participate directly in the propagation of intracellular signaling in response to TGF-beta binding (1). TGF-beta RIII typically functions as a coreceptor for TGF-beta by binding the ligand with high affinity in order to regulate signaling. TGF-beta RIII contains a large glycosylated extracellular domain and a small intracellular domain.

FAS-associated death domain protein (FADD) is a 23 kDa adaptor protein involved in initiating apoptosis. FADD is best known for its involvement in extrinsic/death receptor-mediated apoptosis, but it is also involved in initiating necroptosis with serine/threonine kinases RIPK1 and RIPK3 (1). FADD binds to receptors of the tumor necrosis factor (TNF) superfamily through its C-terminal death domain (DD). During extrinsic apoptosis, binding of the Fas-ligand causes trimerization of the Fas-receptor which then binds to FADD via the DD domain.

Cathepsins are a family of lysosomal proteases (serine, aspartic and cysteine proteases) that acts in conjunction with lipases and nucleases to degrade biological macromolecules in the lysosomes (1). While most cathepsins are ubiquitously expressed to support normal lysosomal degradation, cathepsin B is unique for its role in various pathologies and malignancies (2). Cathepsin B is often overexpressed and alternatively spliced in cancer cells (2).

SLC34A1 encodes the 69 kDa sodium-dependent phosphate transport protein 2A (Npt2a). SLC34A is a member of the type II sodium-phosphate co-transporter family, along with SLC34A3 which encodes Npt2c. These proteins are abundantly expressed along the proximal tubules of the kidneys where most of the filtered inorganic phosphate (Pi) is reabsorbed into the body. Renal reabsorption of Pi directly regulates blood phosphate levels, important for many metabolic processes.

Aside from their important role in apoptosis, caspases also play an important role in inflammatory processes. Humans express four inflammatory caspases: Caspase-1, -4, -5, and -12. Caspase-12 is a 48 kDa protein localized to the ER and involved in the ER stress response. Caspase-12 contains a caspase-associated recruitment domain (CARD) and two catalytic domains, p20 and p10 (1).

Monocyte chemotractant protein-1 (MCP-1), also known as CCL2, is a key chemokine involved in the migration of monocytes and macrophages to sites of active inflammation. It is a member of the C-C/beta family of cytokines, characterized by the Cys-Cys sequence at its N-terminus (1). MCP-1 is tethered to endothelial cells via glycosaminoglycans within the plasma membrane (2). MCP-1 cleavage by MMP-12 is necessary for MCP-1 to interact with its receptor CCR2.

Antibodies play an important role in the innate immune system by circulating in the bloodstream to fight off invading pathogens. IgG is the most prevalent of the five classes of antibodies (IgA, IgD, IgE, IgG, and IgM) and is the only one transmitted from a mother to her offspring. IgG is transported across the epithelium of the placenta by the neonatal Fc receptor (FcRn) (1). FcRn is a 40 kDa protein encoded by the FCGRT gene. FcRn binds to the Fc domain of IgG and transports the antibody in a pH dependent mechanism.

While known for their role in programmed cell death, caspases are also essential for mediating inflammatory responses and innate immunity. Binding of microbial molecules by pattern recognition receptors triggers the formation of the multiprotein inflammasome complex and the activation of caspase-1 (1). Caspase-1 is then able to mediate the activation and secretion of proinflammatory cytokines including interleukin-1. In addition to caspase-1, caspase-11 also plays an important role during the inflammatory response.

alpha-Synuclein is a 14 kDa protein encoded by the SNCA gene that is abundantly expressed in neurons. Within the neuron, alpha-Synuclein is densely localized on presynaptic terminals, indicating a potential role in synaptic transmission. Nitration at specific tyrosine residues promotes misfolding and aggregation of alpha-Synuclein. These aggregates are a major component of Lewy bodies, characteristic lesions of neurodegenerative disorders known as synucleinopathies.

Caspases are endoproteases that play important roles in the regulation of cell death and apoptosis. Caspase active sites contain a catalytic cysteine residue essential for the proteolytic cleavage of their substrates at conserved aspartic acid residues (1). Caspases are produced as inactive procaspase monomers in order to regulate their activity. Upon dimerization procaspases are cleaved to produce their active form (1). Caspases are typically grouped by their role in either cell death or inflammation.