LKB1: a S/T protein kinase of the CAMKL family. A tumor suppressor that helps control cell structure, polarity, apoptosis and energy homeostasis. Phosphorylates AGS3 (activator of G-protein signaling 3) GPR domains, regulating the interaction of GPR-containing proteins with G-proteins. A cytosolic protein complex comprised of LKB1, the pseudokinase STRAD, and the MO25 scaffold protein. Activates AMPK and several related protein kinases. AMPK plays a predominant role as the master regulator of cellular energy homeostasis, controlling downstream effectors that regulate cell growth and apoptosis in response to cellular ATP concentrations. The Lkb1/Strad/Mo25 complex can polarize single epithelial cells, leading to the formation of a brush border containing microvilli on the apical surface. Mutation in the corresponding gene causes Peutz-Jeghers syndrome (PJS), an autosomal dominant disorder characterized by benign GI tract polyps and dark skin lesions of the mouth, hands and feet. A variety of other LKB1 gene mutations have been associated with the formation of sporadic cancers in several tissues.
Protein type: Protein kinase, CAMK; Protein kinase, Ser/Thr (non-receptor); EC 2.7.11.1; Kinase, protein; Autophagy; Tumor suppressor; CAMK group; CAMKL family; LKB subfamily
Chromosomal Location of Human Ortholog: 19p13.3
Cellular Component: mitochondrion; membrane; cytoplasm; nucleus; cytosol
Molecular Function: protein serine/threonine kinase activity; protein binding; p53 binding; protein complex binding; magnesium ion binding; protein kinase activator activity; LRR domain binding; ATP binding
Biological Process: response to glucagon stimulus; Golgi localization; protein heterooligomerization; protein amino acid autophosphorylation; Wnt receptor signaling pathway through beta-catenin; glucose homeostasis; response to lipid; protein amino acid phosphorylation; T cell receptor signaling pathway; anoikis; positive regulation of gluconeogenesis; negative regulation of cell proliferation; regulation of fatty acid biosynthetic process; vasculature development; tissue homeostasis; regulation of cell growth; cell cycle arrest; positive thymic T cell selection; positive regulation of transforming growth factor beta receptor signaling pathway; regulation of Wnt receptor signaling pathway; regulation of protein kinase B signaling cascade; positive regulation of peptidyl-tyrosine phosphorylation; axonogenesis; establishment of cell polarity; energy reserve metabolic process; activation of protein kinase activity; insulin receptor signaling pathway; autophagy; positive regulation of axonogenesis; response to ionizing radiation; negative regulation of cell growth; response to DNA damage stimulus; spermatid development
Disease: Pancreatic Cancer; Testicular Germ Cell Tumor; Peutz-jeghers Syndrome
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