Story highlights Scientists solved a mystery of how cells deliver molecules

All three work at American universities

Prize announcements continue with physics Tuesday

Each prize, endowed by Alfred Nobel in 1895, comes with $1.2 million

Two Americans and a German shared the Nobel Prize in physiology or medicine this year.

Americans James E. Rothman and Randy W. Schekman, and German Thomas C. Sudhof were awarded the prize Monday for discoveries of how the body's cells decide when and where to deliver the molecules they produce.

The Nobel Assembly said the three "have solved the mystery of how the cell organizes its transport system."

Their work focuses on tiny bubbles inside cells called vesicles, which move hormones and other molecules within cells and sometimes outside them, such as when insulin is released into the bloodstream.

Disruptions of this delivery system contribute to diabetes, neurological diseases and immunological disorders.

Winners of the 2013 Medicine Nobel Prize

Photos: Photos: Nobel Prize winners of 2013 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Yale University professor Robert Shiller, famous for his warnings of the housing and Internet bubbles, is one of three Americans who were awarded the Nobel Prize in economics on Monday, October 14. The Nobel committee recognized Shiller and University of Chicago professors Eugene Fama and Lars Peter Hansen for their work on the pricing of financial assets. Hide Caption 1 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Hansen is congratulated by a friend Monday, October 14, after learning he had won the Nobel Prize. Hansen, Shiller and Fama concluded that while predicting the short-term price of stocks and bonds is virtually impossible, it is possible to forecast over longer periods. Hide Caption 2 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Fama prepares to leave his home to teach his morning class after learning he had won the Nobel Prize on Monday, October 14. Hide Caption 3 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Director General Ahmet Uzumcu of the Organisation for the Prohibition of Chemical Weapons comments on the organization being awarded the Nobel Peace Prize during a press conference in The Hague, Netherlands, on Friday, October 11. The organization won the Nobel Peace Prize for its efforts to help eliminate the Syrian army's stockpiles of poison gas and it's long-time efforts to eliminate chemical weapons and weapons of mass destruction. Hide Caption 4 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Canadian short story writer Alice Munro, 82, was awarded the Nobel Prize in literature on Thursday, October 10. Here, Munro faces reporters after receiving the Man Booker International Prize in Dublin, Ireland, in June 2009. Hide Caption 5 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – In awarding her the Nobel Prize, the Swedish Royal Academy of Sciences called Munro the "master of the contemporary short story." The prize committee compared her to the 19th-century Russian great Anton Chekhov. "Munro is acclaimed for her finely tuned storytelling, which is characterized by clarity and psychological realism," the committee said. Hide Caption 6 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Arieh Warshel, a University of Southern California professor of chemistry and biochemistry, at his Los Angeles home on Wednesday, October 9, after learning the Nobel Prize in chemistry had been awarded to him, Martin Karplus and Michael Levitt. The three received the honor for their work in creating complex computer programs used to display intricate models of molecules. Hide Caption 7 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Martin Karplus describes molecular behavior as he speaks to reporters at Harvard University in Cambridge, Massachusetts, after being awarded the Nobel Prize in chemistry on October 9. The three men's work allows researchers to study chemical reactions, which take place very quickly, at a slower pace using a computer. Hide Caption 8 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Biophysicist Michael Levitt at a news conference after winning the Nobel Prize in chemistry on October 9 at Stanford University in Stanford, California. The computer programs the men created eliminate the need for some lab testing. One example would be helping to reduce the necessity of testing a new drug on animals, Hide Caption 9 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – François Englert, left and colleague Peter Higgs received the 2013 Nobel Prize in physics for their research on a mechanism that explains why matter in the universe has mass. The physicists predicted the existence of the Higgs boson particle nearly 50 years before its discovery. Hide Caption 10 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Confirmation of the Higgs boson helped resolve a longstanding puzzle in the Standard Model of particle physics, a theory that lays out the basics of how elementary particles and forces interact in the universe. This image of a proton-proton collision produced in the Large Hadron Collider in Switzerland shows characteristics in line with the decay of a Higgs boson, helping prove the particle's existence. Hide Caption 11 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Yale University professor James Rothman, pictured, shared the Nobel Prize in medicine with Randy Schekman of the University of California, Berkeley, and Dr. Thomas Sudhof of Stanford University for their discoveries of how the body's cells decide when and where to deliver the molecules they produce. Rothman detailed how protein machinery allows vesicles in cells to fuse with their targets to permit the transfer of molecular cargo Hide Caption 12 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Stanford University professor Thomas Sudhof talks with a journalist in Baeza, Spain, on October 7. The trio's discovery will help provide insights into diabetes, immune disorders and other diseases. Hide Caption 13 of 14 Photos: Photos: Nobel Prize winners of 2013 Nobel Prize winners of 2013 – Randy Schekman speaks at the University of California, Berkeley, on October 7 after learning he and two others had won the Nobel Prize in medicine. Hide Caption 14 of 14

Rothman, a professor at Yale University, detailed how protein machinery allows vesicles in cells to fuse with their targets to permit the transfer of molecular cargo.

Schekman, a professor at the University of California, Berkeley, was honored for discovering a set of genes required for the "vesicle traffic."

Sudhof, a professor at Stanford University, showed how vesicles are instructed precisely when to release molecules.

Schekman and Sudhof also are investigators at Howard Hughes Medical Institute.

Monday's ceremony at the Karolinska Institute in Stockholm, Sweden, will be followed by the announcement of the physics prize Tuesday, the chemistry prize Wednesday and the economics prize on October 14.

The Nobel Peace Prize will be awarded in Oslo, Norway, on Friday. The prize for literature will be awarded on a date to be announced later. Each prize comes with 8 million Swedish kronor ($1.2 million).

Swedish industrialist Alfred Nobel created the prizes in 1895 to honor work in physics, chemistry, literature and peace. The first economics prize was awarded in 1969.

In 2012, the medical Nobel Prize was awarded to Sir John B. Gurdon of England and Shinya Yamanaka of Japan for work on reprogramming cells. Their work paved the way for treatment breakthroughs.