protein serine/threonine kinase activity

Definition

Target type: molecularfunction

Catalysis of the reactions: ATP + protein serine = ADP + protein serine phosphate, and ATP + protein threonine = ADP + protein threonine phosphate. [GOC:bf, MetaCyc:PROTEIN-KINASE-RXN, PMID:2956925]

Protein serine/threonine kinases (PSTKs) catalyze the transfer of a phosphate group from ATP to the hydroxyl group of serine or threonine residues on target proteins. This phosphorylation event is a crucial regulatory mechanism in cellular signaling pathways, affecting a wide range of cellular processes, including cell growth, differentiation, metabolism, and apoptosis.

The catalytic domain of PSTKs typically consists of a conserved structure containing a glycine-rich loop, a catalytic loop, and an activation loop. The glycine-rich loop interacts with ATP, while the catalytic loop contains the active site residues responsible for phosphate transfer. The activation loop undergoes conformational changes upon phosphorylation, which regulates the kinase activity.

PSTKs are highly specific for their substrates, often recognizing short linear motifs within the target protein. These motifs typically contain a basic residue followed by a serine or threonine residue, and may also include additional residues that contribute to substrate recognition.

The activity of PSTKs is tightly regulated by various mechanisms, including phosphorylation, protein-protein interactions, and binding of small molecules. These regulatory mechanisms ensure that kinases are only active when and where they are needed.

Upon phosphorylation, target proteins can undergo conformational changes, alter their interactions with other molecules, or become activated or deactivated. This phosphorylation-dependent regulation allows PSTKs to play crucial roles in signaling pathways, coordinating complex cellular responses to external stimuli.'
"

Proteins (420)

Compounds (1,208)