부산대학교 도서관

Via functional complementation we have isolated the Hansenula polymorpha PDD1gene essential for selective, macroautophagic peroxisome degradation. HpPDD1encodes a 116 kDa protein with high similarity (42% identity) to Saccharomyces cerevisiaeVps34p, which has been implicated in vacuolar protein sorting and endocytosis. Western blotting experiments revealed that HpPDD1is expressed constitutively. In a H. polymorpha pdd1disruption strain peroxisome degradation is fully impaired. Sequestered peroxisomes, typical for the first stage of peroxisome degradation in H. polymorpha, were never observed, suggesting that HpPdd1p plays a role in the tagging of redundant peroxisomes and/or sequestration of these organelles from the cytosol. Possibly, HpPdd1p is the functional homologue of ScVps34p, because—like S. cerevisiae vps34mutants—H. polymorpha pdd1mutants are temperature‐sensitive for growth and are impaired in the sorting of vacuolar carboxypeptidase Y. Moreover, HpPdd1p is associated to membranes, as was also observed for ScVps34p. Copyright © 1999 John Wiley & Sons, Ltd.