| Autor: |
Dobriyal N; Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India., Tripathi P; Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India., Sarkar S; Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India.; Department of Biology, Boston University, Boston, MA, 02215, USA., Tak Y; Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India., Verma AK; Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India., Sahi C; Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India. sahi@iiserb.ac.in. |
| Abstrakt: |
J proteins are obligate co-chaperones of Hsp70s. Via their signature J domain, all J proteins interact with their partner Hsp70s and stimulate their weak ATPase activity, which is vital for Hsp70 functions. The dependency of J proteins on their J domain is such that mutations in critical amino acids in the J domain often results into a null phenotype for a particular J protein. Here, we show that the J domain of Djp1, a cytosolic J protein important for peroxisomal protein import in Saccharomyces cerevisiae, is partially dispensable. A complete deletion of Djp1 J domain resulted into only partial loss in peroxisomal protein import function. Instead, the C-terminal domain of Djp1 was found to be essential for proper localization of the peroxisomal targeted GFP-PTS1. Furthermore, we show that Caj1, another cytosolic J protein, also has some role in peroxisomal protein import. Caj1 was found to be partially redundant with Djp1 as cells lacking both Djp1 and Caj1 resulted into a much more severe defect in GFP-PTS1 localization. Based on these results, we propose that dispensability of J domains could be attributed to genetic redundancy between different J proteins sharing common structural topology and cellular localization. |
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