Updated publication reference for PubMed record(s): 29914620. Proteins exhibit dynamics in their expression level in response to intracellular and extracellular signals. Regulation of protein turnover allows cells to rapidly and efficiently remodel their proteomes. It is known that proteins can show very different turnover rates in different tissue of the same organism, but little is known about protein turnover rates in different brain cell types. We used a dynamic SILAC approach to determine protein half-lives in primary hippocampal cultures (containing a mixture of neurons and glia cells) as well as in neuron-enriched and glia-enriched cultures. We determined the protein half-lives for over 5100 proteins and found half-lives ranging from <1 to > 20 days with a median half-life of 5.4 days in mixed cultures. Membrane proteins as a group were shorter-lived and mitochondrial proteins, surprisingly, were longer-lived. Proteins in glia possessed significantly shorter half-lives than the same proteins in neurons. The presence of glia sped up or slowed down the half-lives of neuronal proteins. Our results demonstrate that both the cell-type of origin as well as the nature of the extracellular environment have potent influences on protein turnover.