Heat Responsive Protein 12 (HRSP12)

HRSP12 was coextracted with H1 and HMG proteins from rat liver by 5% perchloric acid, and they designated it PSP for """perchloric acid-soluble protein.""" They cloned the rat gene by screening a liver cDNA expression library with anti-PSP antibodies. The PSP gene encodes a predicted 136-amino acid protein that inhibits protein synthesis at the initiation stage in a cell-free system. The protein is 82% identical to rat PSP and is similar to a hypothetical family of small (15-kD) proteins found in both prokaryotes and eukaryotes, all of which have a highly conserved C-terminal domain. p14.5 inhibits in vitro protein synthesis. On Northern blots, p14.5 is expressed as an approximately 1-kb mRNA, and is found primarily in liver and kidney.