Exploitation of the ribosomal protein L10 R98S mutation to enhance recombinant protein production in mammalian cells

Mammalian cells are commonly used to produce recombinant protein therapeutics, but suffer from a high cost per mg of protein produced. There is therefore great interest in improving protein yields to reduce production cost. We present an entirely novel approach to reach this goal through direct engineering of the cellular translation machinery by introducing the R98S point mutation in the catalytically essential ribosomal protein L10 (RPL10-R98S). Our data support that RPL10-R98S enhances translation levels and fidelity and reduces proteasomal activity in lymphoid Ba/F3 and Jurkat cell models. In HEK293T cells cultured in chemically defined medium, knock-in of RPL10-R98S was associated with a 1.7- to 2.5-fold increased production of four transiently expressed recombinant proteins and 1.7-fold for one out of two stably expressed proteins. In CHO-S cells, eGFP reached a 2-fold increased expression under stable but not transient conditions, but there was no production benefit for monoclonal antibodies. The RPL10-R98S associated production gain thus depends on culture conditions, cell type, and the nature of the expressed protein. Our study demonstrates the potential for using a ribosomal protein mutation for pharmaceutical protein production gains, and further research on how various factors influence RPL10-R98S phenotypes can maximize its exploitability for the mammalian protein production industry.