NACA (nascent polypeptide associated complex subunit alpha) encodes the alpha subunit of the nascent polypeptide-associated complex (NAC), which plays essential roles in cotranslational protein processing and targeting. NAC is a heterodimeric complex that reversibly binds to eukaryotic ribosomes in direct proximity to newly synthesized polypeptides as they emerge from the ribosome 1. The complex orchestrates cotranslational protein modifications by assembling a multienzyme complex with methionine aminopeptidase 1 (MetAP1) and N-acetyltransferase A (NatA), pre-positioning their active sites for sequential N-terminal methionine excision and acetylation of nascent proteins 2. NAC also functions as a negative regulator of inappropriate protein targeting to the endoplasmic reticulum and may positively regulate mitochondrial protein import 1. Additionally, NACA responds to exercise stimuli, with acute aerobic exercise inducing its phosphorylation as part of broader phosphoproteomic changes in skeletal muscle 3. The protein has also been implicated in cancer stemness signatures that predict immunotherapy response, suggesting potential therapeutic relevance 4. These findings establish NACA as a critical regulator of protein biogenesis and cellular metabolism.