Low-molecular-weight chromium-binding substance (Chromodulin) (LMWCr)

Apochromodulin is the inactive, chromium-free form of the low-molecular-weight chromium-binding substance (LMWCr), also known as chromodulin. It is a small oligopeptide (approximately 1.5 kDa) found in the cytosol and nucleus of insulin-sensitive cells, such as those in the liver, muscle, and adipose tissue. Apochromodulin plays a vital role in the autoamplification of insulin signaling; upon the binding of insulin to its receptor, trivalent chromium (Cr3+) is transported into the cell and sequestered by apochromodulin. This binding converts the peptide into its active form, holochromodulin, which then interacts with the intracellular beta-subunit of the insulin receptor to enhance its tyrosine kinase activity by several-fold. This mechanism facilitates the translocation of glucose transporters (GLUT4) to the cell membrane, thereby increasing glucose uptake and improving insulin sensitivity. Consequently, the chromodulin system is a key target for chromium-based therapies and supplements used to manage type 2 diabetes and metabolic disorders.

Other names

ChromodulinApochromodulinLMWCrLow-molecular-weight chromium-binding substance

Binds four trivalent chromium ions to form active holochromodulin, which then binds to the insulin receptor's tyrosine kinase domain to amplify insulin signaling.