autophosphoryleren

Autophosphosphoren or autophosphoryleren refers to a biochemical process in which a protein kinase adds a phosphate group from ATP to one of its own amino acid residues, typically serine, threonine, or tyrosine. In English, the term autophosphorylation is standard; autophosphoryleren is encountered in Dutch or German-language texts as the infinitive form of the verb.

Mechanism and forms

Autophosphorylation can occur in cis, where the kinase phosphorylates its own active site, or in trans, where one kinase molecule phosphorylates another within a dimer or oligomer. In many receptor tyrosine kinases, ligand-induced dimerization promotes trans-autophosphorylation on multiple tyrosine residues in the cytoplasmic region. This modification often increases catalytic activity and creates docking sites for downstream signaling proteins containing SH2 or PTB domains, thereby propagating signal cascades.

Biological contexts

Autophosphorylation is a widespread regulatory mechanism in both eukaryotic and prokaryotic systems. In two-component bacterial signaling systems, histidine kinases autophosphorylate on a histidine residue and subsequently transfer the phosphate to a response regulator. Eukaryotic serine/threonine or tyrosine autophosphorylation modulates diverse processes such as cell growth, differentiation, metabolism, and immune responses.

Significance and implications

Regulated autophosphorylation is essential for proper cellular signaling. Aberrant autophosphorylation, including constitutive activation of receptors, is associated with diseases such as cancer and can influence therapy responses. Understanding the specific residues, context, and partners involved is crucial for deciphering signaling networks and targeting kinases in medical applications.