PRKAB1
Description
The PRKAB1 (protein kinase AMP-activated non-catalytic subunit beta 1) is a protein-coding gene located on chromosome 12.
PRKAB1 encodes the 5'-AMP-activated protein kinase subunit beta-1, a regulatory subunit of the AMP-activated protein kinase (AMPK). AMPK is a heterotrimer comprising an alpha catalytic subunit and non-catalytic beta and gamma subunits. AMPK serves as an essential energy sensor, monitoring cellular energy status. In response to cellular metabolic stresses, AMPK is activated, leading to phosphorylation and inactivation of acetyl-CoA carboxylase (ACC) and beta-hydroxy beta-methylglutaryl-CoA reductase (HMGCR), key enzymes regulating de novo biosynthesis of fatty acid and cholesterol. PRKAB1 may act as a positive regulator of AMPK activity. Myristoylation and phosphorylation of PRKAB1 have been shown to influence AMPK enzyme activity and cellular localization. Additionally, PRKAB1 can function as an adaptor molecule, mediating the association of the AMPK complex. PRKAB1 interacts with PRKAG2 and PRKAG1. The 5'-AMP-activated protein kinase beta subunit interaction domain (AMPKBI) is a conserved domain found in the beta subunit of the 5-AMP-activated protein kinase complex, and its yeast homologues Sip1 (SNF1-interacting protein 1), Sip2 (SNF1-interacting protein 2), and Gal83 (galactose metabolism 83), which are found in the SNF1 (sucrose non-fermenting) kinase complex. This region facilitates the interaction of this subunit with the kinase complex, though it is not solely responsible for the interaction, and the interacting partner remains unknown.
PRKAB1 is a non-catalytic subunit of AMP-activated protein kinase (AMPK), an essential energy sensor that regulates cellular energy metabolism. When intracellular ATP levels decline, AMPK activates energy-producing pathways while inhibiting energy-consuming processes, such as protein, carbohydrate, and lipid biosynthesis, as well as cell growth and proliferation. AMPK achieves this by directly phosphorylating metabolic enzymes and through longer-term effects by phosphorylating transcription regulators. PRKAB1 also acts as a regulator of cellular polarity by remodeling the actin cytoskeleton, likely through indirect activation of myosin. As a scaffold protein, PRKAB1's C-terminus bridges the alpha (PRKAA1 or PRKAA2) and gamma subunits (PRKAG1, PRKAG2, or PRKAG3) of the AMPK complex.
PRKAB1 is also known as AMPK, HAMPKb.
