Updated project metadata. Rice grains are rich in starch but are deficient in proteins containing essential amino acids such as lysine and threonine. Therefore, efforts have been made to improve the nutritional value of rice by overexpressing the genes involved in lysine biosynthesis and/or suppression of lysine catabolism that led to the increased protein content in rice grains. Despite the economic and nutritional benefits rice, the protein accumulation mechanisms are largely elusive. Therefore, to explore the comprehensive proteome profiles, three different parts of rice grains including embryo, endosperm, bran were harvested from weedy rice cultivars (cv. Dharial) and its EMS mutant (DM) having 9.3 and 14.8% of protein content in rice grains, respectively. Here, we utilized a label-free quantitative proteomic analysis and this approach led to the identification of total 5,821 proteins. Of these, 322, 723, and 550 proteins revealed significant differences in their abundance in rice embryo, endosperm, and bran, respectively. Functional classification of identified proteins revealed that enrichment of proteins associated with nitrogen compound biosynthesis and transport, intracellular transport, localization, protein/amino acid synthesis, and photosynthesis, among others were observed in endosperm and bran of high protein mutant rice cultivar. Taken together, the current study uncovers the proteome changes and highlight the various functions of metabolic pathways associated with protein accumulation in rice.