AKAIN1 (A-kinase anchor inhibitor 1) is a PKA-binding protein that functions as a negative regulator of protein kinase A (PKA) subcellular localization. The protein binds specifically to type II regulatory subunits of PKA and blocks AKAP-mediated subcellular targeting of PKA 1, effectively disrupting the normal PKA-AKAP interaction mechanism that directs kinase activity to specific cellular compartments. This inhibitory function suggests AKAIN1 acts as an endogenous disruptor peptide for PKA signaling. AKAIN1 is preferentially expressed in neural tissues 1. The gene has emerged as a potential disease biomarker in two contexts: downregulation in Alzheimer's disease pathology, where it was identified as one of two down-regulated genes among key differentially expressed genes in the entorhinal cortex and may participate in inflammatory pathway dysregulation 2; and elevated expression in multiple myeloma, where high AKAIN1 levels correlate with poor prognostic indicators including increased International Staging System stage, reduced treatment response rates, and shortened progression-free and overall survival 3. These findings indicate AKAIN1 functions as a negative regulator of PKA signaling with potential clinical relevance in neurodegenerative and hematologic malignancies, though the mechanistic basis for its expression changes in disease remains to be elucidated.