Updated project metadata. Protein Kinase A (PKA) is a widely studied protein that has been viewed by most investigators as a single entity, although its catalytic subunits are coded in the genome by two separate genes, PKA catalytic alpha (Gene symbol: Prkaca) and PKA catalytic beta Gene symbol: Prkacb). At an amino-acid level, the two are 91.5 percent identical and the catalytic domains are virtually identical. (Footnote: A third entity PKA catalytic gamma, is not widely expressed and will not be considered here.) We have recently succeeded in using CRISPR-Cas9 to create disruptive mutations in both PKA genes (PKA double KO, or PKA dKO) in vasopressin-responsive kidney epithelial cells (mpkCCD cells). Here we carry out mass spectrometry based quantitative proteomics and phosphoproteomics separately in PKA catalytic-alpha and PKA catalytic-beta single knockouts address the issue of function difference between these two PKA catalytic subunits.