Secretory helpers for enhanced production of heterologous proteins in .

Depending on the suboptimal factor, the target protein secretion can be over 1000-fold below the theoretical maximum. The bottlenecks may be alleviated by co-overexpression of "secretory helpers" (). Here we proposed twelve functionally spanning the whole transcription-translation-translocation-folding-maturation-excretion pipeline. The genes were co-transformed with an easy-to-track reporter, and tested less than two temperatures. Our results indicated a clear distinction in the effects triggered by involved in either synthesis or trafficking of the heterologous polypeptides. For superior operation of synthesis-related , namely and , the secretory pathway's capacity must be released by applying decreased temperature (25 °C). The other considered (e.g. ) did not give such spectacular results in the amounts of the target heterologous polypeptide, but allowed to maintain secretory capacity under unfavorable thermal conditions. This study provides generalizable guidelines for cloning/culturing strategies aiming at enhancement of heterologous protein secretion in .