Kinase Family SGK

Kinase Classification: Group AGC: Family SGK

Serum and Glucocorticoid regulated Kinases are second messenger kinases related to Akt that are activated by extracellular stimuli.

Evolution

SGK is found in most animals, though lost in Drosophila and most other Diptera. There are 3 vertebrate members, SGK1, SGK2, SGK3. Fungi have proteins with similarity to both SGK and Akt, but are not clearly members of either family by sequence similarity, while the more basal Dictyostelium has a clear Akt and likely SGK.

Domain Structure

Most SGKs have an N-terminal PX domain followed by a kinase domain with the characteristic AGC extension. The PX domain in vertebrate SGK1 is divergent and often missed by domain profiles, while the C. elegans homolog (W10G6.2/sgk-1) has a PX domain that is missing from domain databases but present on an Alphafold model. Vertebrate SGK2 is N-terminally truncated and lacks the PX domain.