Ernest Peralta. Photo by Jon Chase.

A funeral Mass for Ernest G. Peralta, professor of molecular and cellular biology, will take place at 11 a.m. on Sat., May 22, at St. Peter's Parish in Cambridge (96 Concord Ave.). Interment will follow at Mt. Auburn Cemetery.

The 40-year-old scientist died in his Cambridge home on May 17 after a three-year battle with brain cancer.

In his research, Peralta tuned in on the chemical messages that cells use to regulate much of the basic business of life. His studies significantly expanded knowledge of how the major neurotransmitter acetylcholine participates in such "cell talk" to speed or slow heart rates, record information in the brain, constrict lung cells, or release hormones of the endocrine system.

Peralta completed his bachelor's degree at Northwestern University in 1981 and his doctorate at Indiana University in 1986. As a graduate student, he made an important contribution to understanding the tumor-generating process of crown galls in plants.

After leaving Indiana, Peralta worked with Genentech, the San Francisco biotechnology firm, where he discovered five receptor molecules (on cell surfaces) for acetylcholine and also found that this substance could deliver various messages to different cells. (Only one kind of acetylcholine receptor had previously been thought to exist, and acetylcholine itself had been thought to carry only one message.)

Although this work brought him tenure offers at age 29, Peralta opted instead to come to Harvard in 1989 as an assistant professor. He rose to associate professor in 1993 and became a full professor in 1996.

Peralta studied cell communication by manipulating genes to alter messages between cells. By observing the results of introducing "foreign-speaking" genes, he and his students gained new insights into the complexities of cell-to-cell transactions. Such basic research has opened many avenues in medicine, including the potential for developing better treatments for high blood pressure and migraine headaches.

Peralta's laboratory -- considered one of the most dynamic in the Department of Molecular and Cellular Biology -- became a magnet for graduate students. His Harvard research group made key findings concerning the regulation of potassium channels by acetylcholine, which elucidated the molecular mechanism by which acetylcholine controls the heartbeat. Peralta's laboratory remained active and productive throughout his illness.

A dedicated and enthusiastic teacher, Peralta taught biochemistry and molecular biology to undergraduates as well as advanced courses in cell communication. Colleagues recall him as a man whose gentle demeanor and easygoing style belied a fierce determination to uncover the mechanism of cell communication at the molecular level.

Outside the laboratory, Peralta was an avid basketball, tennis, and volleyball player. He was an accomplished classical guitarist, and he enjoyed the outdoors and the visual arts (he married a computer-graphics artist). At Northwestern, a strong interest in economics nearly gave him a double major, and his passion for biology almost led to medical school.

Peralta's peers held his work in high regard, and he served on various editorial boards and grant-review groups. His research brought him the Presidential Young Investigator Award (National Science Foundation) and the McKnight Scholar Award in Neuroscience. He was also a Searle Scholar.

Peralta was born in St. Louis, Mo., on April 19, 1959.

He leaves his wife, Renate Hellmiss-Peralta; his parents, Lydia and Ben; and three sisters: Mary, Elisabeth, and Rita.

The family requests that memorial donations be made to the Ernie Peralta Hospice Fund, BankBoston, 615 Concord Ave., Cambridge, MA 02138 (Account #272-97380) or to the Ernie Peralta Student Fund, 7 Divinity Ave., Cambridge, MA 02138.