LKB1 also known as STK11 is a serine/threonine kinase that regulates cell polarity and energy metabolism and functions as a tumor suppressor. LKB1 plays a pivotal role in regulating cellular energy homeostasis, cell polarity, and metabolism by activating AMP-activated protein kinase (AMPK) and other related kinases. The structure of LKB1 includes a conserved kinase domain essential for enzymatic activity, as well as regulatory regions that facilitate interaction with other proteins and substrates. Post-translational modifications of LKB1, such as phosphorylation and ubiquitination, are critical for modulating activity, stability, and localization within the cell, thereby influencing ability to act as a tumor suppressor. Mutations and alterations in LKB1 are strongly associated with Peutz-Jeghers Syndrome (PJS), a hereditary disorder characterized by benign polyps in the gastrointestinal tract, pigmented spots on the lips, and an increased risk of various cancers.