Function of N‐terminal import signals in trypanosome microbodies

Authors:
  • HDH Dörsam
    H Dörsam
  • CCC E Clatyon
    C E Clatyon
Publisher website
Google Scholar
Abstract
The glycosomes of trypanosomes are related to eukaryoticperoxisomes. For many glycosomal and peroxisomal proteins, a C‐terminal SKL‐like tripeptide known as PTS‐1 serves as the targeting signal. For peroxisomes, a second N‐terminal signal (PTS‐2) was demonstrated on rat 3‐ketoacyl‐CoA thiolase. Several glycosomal proteins do not bear a PTS‐1. One such protein, fructose bisphosphate aldolase, has a PTS‐2 homology at its N‐terminus. To find out whether the PTS‐2 pathway exists in trypanosomes, we expressed chloramphenicol acetyltransferase fusion proteins bearing N‐terminal segments of either rat thiolase or trypanosome aldolase. The mammalian PTS‐2 clearly mediated glycosomal import. The aldolase N‐terminus mediated import with variable efficiency depending on the length of the appended sequence. These results provide evidence for the existence of the PTS‐2 pathway in trypanosomes.

This publication has 29 references indexed in Scilit: