Peptidoglycan synthesis occurs at two locations in Staphylococcus aureus — at the cell wall during growth and mid-cell during division — but how peptidoglycan synthesis is spatially regulated throughout the cell cycle is unknown. Do et al. performed a genetic screen to find regulators of peptidoglycan synthesis and identified a membrane protein complex consisting of an amidase (LytH) that trims stem peptides from uncrosslinked peptidoglycan and its regulator to control cell growth. In the absence of LytH, peptidoglycan synthesis was spatially dysregulated, which caused cell growth and division defects. Attenuating the activity of the major peptidoglycan synthase corrected mislocalization defects and compensated for the loss of LytH. The authors propose that the amidase complex regulates the density of peptidoglycan synthase activity at the cell periphery and mid-cell to ensure that cell growth is coordinated with division.