Americans James Rothman and Randy Schekman and German-born researcher Thomas Suedhof won the 2013 Nobel Prize in medicine on Monday for discoveries on how proteins and other materials are transported within cells.

The Nobel committee said their research on “vesicle traffic” — the transport system of our cells — helped scientists understand how “cargo is delivered to the right place at the right time” inside cells.

“Disturbances in this system have deleterious effects and contribute to conditions such as neurological diseases, diabetes and immunological disorders,” the committee said.

The Jewish Rothman is a professor at Yale University while Schekman, also Jewish, is at the University of California, Berkeley. Suedhof joined Stanford University in 2008.

Israeli contenders, Hebrew University professors Howard Cedar and Aharon Razin, were thought to be frontrunners in the runup to the announcement.

Schekman said he was awakened at 1 a.m. at his home in California by the chairman of the prize committee and was still suffering from jetlag after returning from a trip to Germany the night before.

“I wasn’t thinking too straight. I didn’t have anything elegant to say,” he told The Associated Press. “All I could say was ‘Oh my God,’ and that was that.”

He called the prize a wonderful acknowledgment of the work he and his students had done and said he knew it would change his life.

“I called my lab manager and I told him to go buy a couple bottles of Champagne and expect to have a celebration with my lab,” he said.

In the 1970s, Schekman discovered a set of genes that were required for vesicle transport, while Rothman revealed in the 1980s and 1990s how vesicles delivered their cargo to the right places. Also in the ’90s, Suedhof identified the machinery that controls when vesicles release chemical messengers from one brain cell that let it communicate with another.

“This is not an overnight thing. Most of it has been accomplished and developed over many years, if not decades,” Rothman told the AP.

Rothman said he lost grant money for the work recognized by the Nobel committee, but he will now reapply, hoping the Nobel prize will make a difference in receiving funding.

The medicine prize kicked off this year’s Nobel announcements. The awards in physics, chemistry, literature, peace and economics will be announced by other prize juries this week and next. Each prize is worth 8 million Swedish kronor ($1.2 million).

Rothman and Schekman won the Albert Lasker Basic Medical Research Award for their research in 2002 — an award often seen as a precursor of a Nobel Prize. Suedhof won the Lasker award this year.

“I might have been just as happy to have been a practicing primary-care doctor,” he said after winning that prize. “But as a medical student I had interacted with patients suffering from neurodegeneration or acute clinical schizophrenia. It left an indelible mark on my memory.”

Jeremy Berg, former director of the National Institute of General Medical Sciences in Bethesda, Maryland, said Monday’s announcement was “long overdue” and widely expected.

That’s because the winners’ research was “so fundamental, and has driven so much other research,” he said in a telephone interview.

Berg, who now directs the Institute for Personalized Medicine at the University of Pittsburgh, said the work provided the intellectual framework scientists use to study how brain cells communicate and how other cells release hormones. In both cases, vesicles play a key role by delivering their cargo to the cell surface and releasing it to the outside, he said.

So the work has indirectly affected research into virtually all neurological disease as well as other diseases, he said.

Established by Swedish industrialist Alfred Nobel, the Nobel Prizes have been handed out by award committees in Stockholm and Oslo since 1901. The winners always receive their awards on Dec. 10, the anniversary of Nobel’s death in 1896.

Last year’s medicine award went to Britain’s John Gurdon and Japan’s Shinya Yamanaka for their contributions to stem cell science.