protein autophosphorylation

Definition

Target type: biologicalprocess

The phosphorylation by a protein of one or more of its own amino acid residues (cis-autophosphorylation), or residues on an identical protein (trans-autophosphorylation). [ISBN:0198506732]

Protein autophosphorylation is a crucial regulatory mechanism in cellular signaling, where a protein kinase enzyme catalyzes the addition of a phosphate group to a specific amino acid residue within the same protein molecule. This process plays a pivotal role in regulating diverse cellular functions, including cell growth, differentiation, metabolism, and signal transduction.

The autophosphorylation event typically occurs at specific amino acid residues, commonly serine, threonine, or tyrosine, located within the protein's structure. These residues often reside within a specific domain known as the phosphorylation site, which serves as a recognition motif for the kinase enzyme.

The process of autophosphorylation can be initiated by various stimuli, such as ligand binding, changes in cellular conditions, or interactions with other proteins. Upon activation, the kinase enzyme undergoes a conformational change that brings its catalytic domain into proximity with the phosphorylation site on the target protein.

The catalytic domain of the kinase enzyme then facilitates the transfer of a phosphate group from ATP (adenosine triphosphate) to the hydroxyl group of the target amino acid residue. This phosphorylation event alters the protein's conformation, often leading to changes in its activity, stability, or interactions with other molecules.

Autophosphorylation can act as a positive feedback loop, enhancing the kinase's activity by increasing its affinity for substrates or promoting its oligomerization. Alternatively, it can function as a negative feedback mechanism, inhibiting the kinase's activity or triggering its degradation.

In many cases, autophosphorylation creates docking sites for other proteins, facilitating the assembly of protein complexes and the activation of downstream signaling pathways. These pathways can ultimately regulate gene expression, cellular metabolism, or other essential cellular processes.

In summary, protein autophosphorylation is a complex and highly regulated process that plays a central role in cellular signaling. By modifying the structure and function of proteins, autophosphorylation enables cells to respond to diverse stimuli and maintain cellular homeostasis.'
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Proteins (144)

Compounds (1,028)