Serine/threonine-protein kinase that plays a key role in polarization of neurons and axonogenesis, cell cycle progress and insulin secretion. Phosphorylates CDK16, CDC25C, MAPT/TAU, PAK1 and WEE1. Following phosphorylation and activation by STK11/LKB1, acts as a key regulator of polarization of cortical neurons, probably by mediating phosphorylation of microtubule-associated proteins such as MAPT/TAU at 'Thr-523' and 'Ser-573'. Also regulates neuron polarization by mediating phosphorylation of WEE1 at 'Ser-642' in post-mitotic neurons, leading to down-regulate WEE1 activity in polarized neurons. Plays a role in the regulation of the mitotic cell cycle progress and the onset of mitosis. Plays a role in the regulation of insulin secretion in response to elevated glucose levels, probably via phosphorylation of CDK16 and PAK1. While BRSK2 phosphorylated at Thr-175 can inhibit insulin secretion, BRSK2 phosphorylated at Thr-261 can promote insulin secretion. Regulates reorganization of the actin cytoskeleton. May play a role in the apoptotic response triggered by endoplasmic reticulum (ER) stress (By similarity). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] ATP + L-seryl-[tau protein] = ADP + H(+) + O-phospho-L-seryl-[tau protein] ATP + L-threonyl-[tau protein] = ADP + H(+) + O-phospho-L-threonyl-[tau protein] Activated by phosphorylation on Thr-175 by STK11/LKB1. Interacts with FZR1, a regulatory subunit of the APC ubiquitin ligase complex. Interacts with COPS5. Interacts with PAK1 (By similarity). Detected at centrosomes during mitosis. Localizes to the endoplasmic reticulum in response to stress caused by tunicamycin (By similarity). May be phosphorylated at Thr-261 by PKA (By similarity). Phosphorylated at Thr-175 by STK11/LKB1 in complex with STE20-related adapter-alpha (STRADA) pseudo kinase and CAB39. Not phosphorylated at Thr-175 by CaMKK2. In contrast, it is phosphorylated and activated by CaMKK1. May be inactivated via dephosphorylation of Thr-175 by PP2C (By similarity). Polyubiquitinated by the APC complex in conjunction with FZR1, leading to its proteasomal degradation. Targeted for proteasomal degradation by interaction with COPS5. BRSK2 levels change during the cell cycle. BRSK2 levels are low at the G1/S boundary and gradually increase as cells progress into G2 phase. BRSK2 levels decrease rapidly at the end of mitosis (By similarity). Protein synthesis is inhibited by the TSC1-TSC2 complex acting through TORC1 in neurons, leading to regulate neuron polarization. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. SNF1 subfamily.