Nancy M. Deptula, who served more than four decades as an assistant to top Harvard deans and oversaw two prominent Harvard research centers, died last week at her home in Newton. She was 74.

The cause of death was complications from cancer and Parkinson’s disease.

Deptula arrived at Harvard in 1954 as a research assistant in the Russian Research Center. She later became administrative assistant to the Dean of the Graduate School of Arts and Sciences and the Dean of the College. During these years, she compiled a 500-page list of the Administrative Board’s decisions over eight decades, from 1890 to 1970.

In 1977 she moved to Harvard’s Japan Institute and maintained a close relationship with the center’s founder, Edwin O. Reischauer, a former ambassador to Japan who worked at the center until his death in 1990.

Deptula retired in 1995, having risen to the post of Executive Director and watched the Institute grow from a small center for Japanese studies to a major research foundation that funds lecture series and educational programs in both the U.S. and Japan.

“For all intents and purposes, she was the director, for she knew so much more than I about the institute’s history, budget, staff and programs,” said Warren Professor of American History Akira Iriye, who presided over the Institute from 1991 to 1995.

In the early 1990s, reporters came looking for material about Japan’s Crown Princess Masako ’85, who had worked at the institute during her years at Harvard and whose marriage was then in the news.

According to Professor of History Andrew D. Gordon, Deptula dug up Masako’s old pay records and won herself a brief appearance on Japanese television news shows.

Born in Wisconsin, Deptula enrolled at the University of Wisconsin but moved to the East Coast with her husband before finishing her studies. Later, while still working full-time at Harvard, she earned her bachelor’s degree from Wellesley College in a program designed for working women who wanted to go back to school. Her senior thesis won top prize from their history department.

In 1980, the same year she graduated from Wellesley, Deptula was diagnosed with Parkinson’s disease. Despite her illness, she remained an avid bicycler and took trips to the farm she and her husband owned in Maine.

In her later years at Harvard, Deptula sometimes talked of writing a book about the deans whom she had known as a secretary—and even planned to devote a chapter to each dean and title it with a teasing nickname for the man. But she never got around to it.

She is survived by her husband, George, as well as their son, George, and two grandchildren.

Memorial services are planned for 2 p.m. on Feb. 15 at Memorial Church.