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-529' and 'Ser-579'. Also regulates neuron polarization by mediating phosphorylation of WEE1 at 'Ser-642' in postmitotic 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-174 can inhibit insulin secretion (PubMed:22798068), BRSK2 phosphorylated at Thr-260 can promote insulin secretion (PubMed:22669945). Regulates reorganization of the actin cytoskeleton. May play a role in the apoptotic response triggered by endoplasmic reticulum (ER) stress. 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-174 by STK11/LKB1. Interacts with FZR1, a regulatory subunit of the APC ubiquitin ligase complex. Interacts with COPS5. Interacts with PAK1. Detected at centrosomes during mitosis. Localizes to the endoplasmic reticulum in response to stress caused by tunicamycin. Detected in pancreas islets (at protein level). The KEN box motif is required for interaction with FZR1/CDH1 and essential for APC(CDH1)-mediated ubiquitination. Phosphorylated at Thr-174 by STK11/LKB1 in complex with STE20-related adapter-alpha (STRADA) pseudo kinase and CAB39. Not phosphorylated at Thr-174 by CaMKK2. In contrast, it is phosphorylated and activated by CaMKK1. May be inactivated via dephosphorylation of Thr-174 by PP2C. Phosphorylated at Thr-260 by PKA. Phosphorylation at Thr-260 by PKA was not observed in another study (PubMed:18339622), but this may reflect differences in the experimental approach. Phosphorylation at Thr-260 seems to play a role in the regulation of insulin secretion (PubMed:22669945). 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. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. SNF1 subfamily. Truncated C-terminus. Truncated N-terminus.