While our earlier microarray analysis identified a number of possible candidate genes, which may be involved in OsNOA1 function (Yang et al., 2011a), a complementary study of the rice proteome profiles under the same condition has the potential to yield new insights into the biological functions of NOA1 and molecular mechanism of NOA1 associated regulation. In this study, we utilized previously-generated OsNOA1 RNAi lines (Yang et al., 2011a) and newly-generated OsNOA1 overexpression lines to further investigate the function and mechanism of NOA1 in rice. Here we report the proteome changes which include important candidate proteins involved in chloroplast ribosome biogenesis and several classes of proteins with significant changes in response to various levels of OsNOA1 under two different temperature conditions. Our results suggest that OsNOA1 can function in a threshold-dependent manner to regulate the biosynthesis of chloroplast proteins in rice at lower temperatures, and this regulation may be achieved via interactions between NOA1 and chloroplast ribosomes.