Hideko Kaji, PhD

Professor, Department of Biochemistry & Molecular Biology

Kaji, Hideko


1020 Locust Street
Room 456A JAH
Philadelphia, PA 19107

Email Hideko Kaji

215-923-7343 fax

Hideko Kaji, PhD

Professor, Department of Biochemistry & Molecular Biology

Expertise and Research Interests

Translation (protein synthesis) from aminoacyl tRNA consists of four consecutive steps; initiation, elongation, termination, and recycling of the machinery of the protein synthesis for the next round of translation. We discovered the fourth step. We are working on the this step in prokaryotes and eukaryotes. We discovered that a protein called ribosome recycling factor (RRF) is necessary for this step in prokaryotes. This protein is essential for all organisms except for Archaea. In collaboration with other laboratories, we determined the structure of RRF and the ribosomal binding site of RRF. RRF moves in the inter-subunits space of the ribosome during its function like tRNA does. We have recently discovered RRF functions to rescue stalled ribosomes with the help of termination factors RFs in the absence of the termination codon. This is being submitted.
In the eukaryotic cytoplasm, there is no equivalent of RRF for recycling ribosomes. In search for the recycling factor, we discovered recently that eEF3 and ATP functions to disassemble the post-termination complex. The P-site bound peptidyl tRNA is hydrolyzed by eRF1 and 3 to form post-termination complexes. For convenience, we can use puromycin, an antibiotic which reacts with peptidyl tRNA on the P-site to form peptidyl puromycin. Since eEF3 is limited to yeast, the system is a good target of possible anti-fungal agent. Since eEF3 is absent in higher eukaryotes like humans, there must be other protein factor responsible ribosome recycling in the cytoplasm. We are going to find out this protein. These studies are basis of fundamental biology, protein synthesis. The factor we are after may play important role in tumor formation, aging, and development.


PhD, Purdue University



Recipient of the Special Fellowship from the Japanese Government, 1952-1954
Recipient of Association of American College Women Club Fellowship, 1954
Recipient of University of Nebraska Foundation Fellowship, 1954-1956
Recipient of Purdue Foundation Fellowship, 1956 -1958
Recipient of Eli Lilly Fellowship, 1958 -1959
Recipient of Senior NIH Fellowship, 1972 -1973
Recipient of Max Planck Gesellschaft Foundation Fellow, 1972 -1974
Fellow of the American Association for the Advancement of Science, 2011




English, German, Japanese