Ser62

Ser62 is a specific serine residue occupying the 62nd position in the amino acid sequence of certain proteins. In the human tumor suppressor protein p53, Ser62 is located within the central DNA‑binding core domain and is a well‑studied site of post‑translational modification. Phosphorylation of Ser62 by kinases such as ATM, ATR, or extracellular signal‑regulated kinase (ERK) stabilizes the p53 protein by reducing its interaction with the E3 ubiquitin ligase MDM2, thereby enhancing its half‑life. This modification potentiates p53’s ability to activate transcription of target genes involved in cell cycle arrest, apoptosis, or DNA repair in response to genotoxic stress. Anti‑phospho‑Ser62 antibodies are routinely employed in Western blotting and immunohistochemistry to assess p53 activation status in cultured cells and tissue sections.

Alterations in the Ser62 residue can influence p53 function. Substitution of serine by alanine (S62A) prevents phosphorylation at this site and has been shown to diminish p53’s transcriptional activity and cellular response to DNA damage. Conversely, phosphomimetic mutations (S62E or S62D) can partially recapitulate the stabilizing effect of phosphorylation. In some cancers, mutations at or near Ser62 are observed, though they are relatively rare compared to alterations in other residues of p53. Nevertheless, the Ser62 phosphorylation event remains a critical regulatory node that integrates diverse signaling pathways to control p53’s role in maintaining genomic integrity.

Beyond p53, Ser62 also appears in other proteins, often within conserved motifs that may undergo phosphorylation or other modification. In these contexts, Ser62 can serve as a marker for kinase activity, protein–protein interactions, or conformational changes. Techniques such as mass spectrometry, site‑directed mutagenesis, and structural analysis contribute to the broader understanding of Ser62’s functional significance across different biological systems.