Here, we show that, mechanistically, NAT10 regulates 3-phosphoglycerate dehydrogenase (PHGDH) and phosphoserine aminotransferase 1 (PSAT1) via its RNA helicase domain to support the proliferation of metastatic breast cancer cells in the serine/glycine-limited brain microenvironment. Here, PSAT1 is linked to breast cancer.