Two-step induction of cdsA promoters leads to upregulation of the glycolipid MPIase at cold temperature

[摘要] Glycolipid MPIase, essential for membrane protein integration into the cytoplasmic membrane of Escherichia coli, is upregulated at cold temperatures. This upregulation is rapid and sustainable. CdsA, a CDP-diacylglycerol synthase, is a rate-limiting enzyme for MPIase biosynthesis. Upregulation of CdsA is responsible for the increase in the MPIase level at low temperature. Investigation of cdsA regulatory regions revealed at least two cold-inducible promoters, a cold-shock promoter that functions transiently and immediately in the cold, and one that is sustainable in the cold. The stability of the cdsA transcript was comparable with that of tufA, which is not cold-inducible. Thus, cdsA is induced through two-step cold-induction to maintain MPIase at a high level rapidly and sustainably in the cold.

[关键词] glycolipid;low temperature;membrane biogenesis;membrane protein integration;MPIase;preprotein translocation