Leucine carboxyl methyltransferase 1

Leucine carboxyl methyltransferase 1 (LCMT1) is a 334-amino acid protein that catalyzes the methylation of the C-terminal leucine residue of protein phosphatase 2A (PP2A) catalytic subunits, generating alpha-leucine ester modifications (UniProt: Q9UIC8). This post-translational modification is critical for regulating PP2A activity and localization, linking LCMT1 to broad cellular phosphorylation homeostasis.

LCMT1 is widely expressed across tissues and functions within the PP2A regulatory network, which controls dephosphorylation of numerous signaling and structural proteins. No explicit disease associations are documented in UniProt for this gene.

In Alzheimer's disease, LCMT1 is upregulated in post-mortem brain tissue from AD patients compared to age-matched controls (mean log2 fold-change = 1.41; Chaparral AD proteomics). This elevation was detected across subcellular fractions in a TMT-labeled quantitative proteomics study. The functional significance of increased LCMT1 in AD pathology remains to be elucidated but may reflect altered PP2A regulation during neurodegeneration.