The Antisenescence Protein Klotho Is Necessary for FGF23-Induced Phosphaturia Klotho Converts Canonical FGF Receptor into a Specific Receptor for FGF23.Nature 444: 770-774, 2006

Enzyme-linked receptors are proteins that act as both receptor and enzyme, activating multiple intracellular signals. This is a large group of receptors that include the receptor tyrosine kinase (RTK) family. Many growth factors and hormones bind to and activate the RTKs.
Neurotrophin (NT) receptors are a family of RTKs, including trkA, trkB, and trkC (tropomyosin-related kinase) receptors. TrkA is specific for nerve growth factor (NGF), neurotrophin-6, and neurotrophin-7. TrkB binds...

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR activation may...

Rapidly dividing tumors, embryos, and wounded tissues require more oxygen than usual, lowering the oxygen concentration in the blood. At low oxygen or hypoxic conditions, an oxygen-sensitive transcription factor called the hypoxia-inducible factor 1 or HIF1 is activated. HIF1 is a dimeric protein of alpha (ɑ) and beta (β) subunits.  Under optimal oxygen conditions, HIF1β is present in the nucleus while HIF1ɑ remains in the cytosol. HIF1ɑ is hydroxylated by prolyl hydroxylase and factor...

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...

Calcium and phosphate are essential electrolytes in the human body, with calcium being the most abundant mineral. Around 99% of the body's calcium is stored in the skeleton and teeth, forming a crystal lattice of mineral salts in combination with phosphates. Calcium plays crucial roles in various bodily functions such as blood clotting, neurotransmitter release, muscle tone maintenance, and nervous and muscle tissue excitability.
The calcium concentration in blood plasma is primarily regulated...