Isoform 9 of cAMP-dependent protein kinase catalytic subunit beta

Isoform 9 of cAMP-dependent protein kinase catalytic subunit beta (PKA C-beta) is the catalytic subunit of protein kinase A, a key serine/threonine kinase that mediates cAMP-dependent signaling (UniProt: P22694-9). This 41 kDa protein functions as a phosphorylation effector in diverse cellular processes regulated by cyclic adenosine monophosphate.

PKA catalytic subunits are expressed broadly across tissues and play roles in metabolic regulation, gene transcription, and neuronal signaling. The UniProt record does not list specific disease associations for this isoform.

This protein is relevant to Alzheimer's Disease based on proteomics evidence: the isoform is significantly downregulated in human post-mortem AD brain tissue relative to age-matched controls (mean log2 fold-change −1.10; Chaparral AD proteomics). The measurement was obtained from TMT-labeled quantitative proteomics across four subcellular fractions (P2, P3, S2, S3) from AD versus control brain samples. The consistent downregulation across the analyzed fraction(s) suggests reduced PKA C-beta availability in the AD brain proteome, potentially affecting cAMP-dependent signaling pathways implicated in cognitive function.