THE INTRACELLULAR DOMAIN OF THE RABBIT PROLACTIN RECEPTOR IS ABLE TO PROMOTE THE SECRETION OF A PASSENGER PROTEIN VIA AN UNUSUAL SECRETORY PATHWAY IN LEPIDOPTERAN CELLS

We have previously shown that the intracellular domain of the rabbit p rolactin receptor (rbPRL-R), lacking typical signal sequences, was ver y efficiently secreted into the culture medium when expressed in the b aculovirus-insect cell system, We have sought to take advantage of thi s characteristic for secreting cytoplasmic or nuclear proteins. We hav e constructed a series of recombinant viruses expressing a foreign gen e product fused to the intracellular domain of rbPRL-R. Two passenger genes were used, one encoding a cytoplasmic protein (cyclin B) and the other a nuclear protein (cyclin A). The intracellular domain of rbPRL -R was able to promote the export of these two chimeric proteins with a very high efficiency. This new system should prove useful for secret ion of proteins which do not require the post-translational modificati ons of the classical secretory pathway to be fully active.