AUSTIN, Texas — Dr. Alfred Gilman, a Nobel Laureate medical researcher known for groundbreaking work on cells and diseases, has died at the age of 74 after a long illness, the University of Texas Southwestern Medical School said.

Gilman and Martin Rodbell won the 1994 Nobel Prize in Physiology or Medicine for their discovery of the G-protein, the mechanism that receives messages in a human cell and connects them to the correct destination.

Gilman said at the time that his and Rodbell’s work was closely linked to understanding and treating difficult diseases.

“When we understand all those pathways, we’ll have a much better understanding of how to use drugs to control them,” he said after receiving the prize.

Gilman served as the chairman of pharmacology at UT Southwestern for more than two decades. He retired from the Medical Center in 2009, the school said in a news release.

He died on Wednesday, the school said.

Gilman also fought on behalf of science, taking on the Texas Board of Education about five years ago when it wanted to reduce the teaching of evolution in state schools, the school said.

“Failure to provide our children with a sound, modern education puts them at a serious disadvantage when they compete or engage with the rest of the world,” he wrote in an opinion piece in 2009.

Gilman’s interest in science was sparked at the age of about 10 when his father started to take him into his laboratory, he said. The senior Alfred Gilman was founding chairman of pharmacology at the Albert Einstein College of Medicine in New York.

In 2013, Gilman resigned from a Texas cancer research institute championed by disgraced cyclist Lance Armstrong, apparently taking issue with a $20 million grant that was not reviewed by science experts.

“Dr. Gilman was a giant in medical research. His discovery of G proteins and their critical functions is a cornerstone of research across virtually every important domain of medicine,” said Dr. Daniel Podolsky, president of UT Southwestern Medical Center.