Association Between Human (pro)Renin Receptor Lacking Putative Transmembrane and Cytoplasmic Domains with Autographa Californica Multiple Nucleopolyhedrovirus Lacking Other Transmembrane Domains

Human (pro)renin receptors (hPRR) with native putative transmembrane and cytoplasmic domains (hPRR-wTM) were purified from the microsomal fraction of baculovirus-infected Tn-5B1-4 cells. However, hPRR produced with deleted transmembrane and cytoplasmic domains (hPRR-w/oTM) could not be adequately purified. In this report, the expression of hPRR-wTM and hPRR-w/oTM was analysed. hPRR-w/oTM was detected in budded baculovirus (BV) fractions isolated from culture supernatant, whilst hPRR-wTM was not. This suggests that hPRR-w/oTM might be associated with BV. hPRR was expressed in the peripheral domains of the nucleus in infected Sf-9 cells. In contrast, hPRR-w/oTM was observed in punctate domains in the cytoplasm, indicating that hPRR-wTM and hPRR-w/oTM localized in the endoplasmic reticulum (ER) and cytoplasmic organelles, respectively. Moreover, intracellular hPRR-w/oTM did not co-localize in the Golgi apparatus and lysosomes. hPRR-wTM could not be extracted from infected Sf-9 and Tn-5B1-4 cells by Triton X-100 treatment at 4°C. It is suggested that hPRR-wTM might not reside in the plasma membrane and that localization of hPRR-wTM in the ER might result in a lack of association with the BV. hPRR-w/oTM was detected in the BV fraction despite lacking a transmembrane domain, but was not detected in the virus envelope fraction, suggesting that hPRR-w/oTM might be associated with other areas in the BV.