Subtitles section Play video Print subtitles >> HELLO. WELCOME TO TODAY'S WEDNESDAY AFTERNOON LECTURE AT NATIONAL INSTITUTES OF HEALTH. THANK YOU FOR COMING. MY NAME IS JUSTIN TERASKA. I'M AN INVESTIGATOR IN THE LABORATORY OF MOLECULAR BIOPHYSICS IN THE NATIONAL HEART LUNG AND BLOOD INSTITUTE. IT'S MY PLEASURE TO INTRODUCE DR. JAMES ROTHMAN AS TODAY'S WALS SPEAKER. DR. ROTHMAN IS WALS PROFESSOR OF BIOMEDICAL SCIENCES AND CHAIR OF DEPARTMENT OF BIOMEDICAL AT YALE. HE'S ONE OF THE MOST INNOVATIVE AND INFLUENTIAL CELL BIOLOGISTS AND BUY CHEMISTS WORKING OFFER THE LAST FEW DECADES. DURING TENURES AT STANFORD, PRINCETON, INVENTORY DEBT R, COLUMBIA AN YALE, -- CLONE KETTERING AND YALE, THIS IS INCLUDED SEMINOLE DISCOVERIES RELATED TO HOW PROTEINS INSERT INTO MEMBRANES. HOW VESICALES TRAFFIC THROUGH THE CELL, AND HOW VESICALES FUSE WITH THE MEMBRANE, A PROCESS CALLED EXOCYTOSIS. ASIDE FROM THE BIOLOGICAL DISCOVERIES HIS LAB HAS INVENTED IMPORTANT METHODS INCLUDING IN VITRO RECONSTITUTION OF VESICAL TRAFFICKING PATHWAYS WHICH HAS REALLY ALLOWED THE COMPLEX STEPS OF VESICAL TRAFFICKING TO BE TEASED APART AT THEIR MOST FUNDAMENTAL LEVEL H. ADDITIONALLY DEVELOPED NOVEL PH FLUORESCENCE PROTEINS THAT ALLOW INDIVIDUAL SYNAPSES AND SINGLE VESICALES TO BE WATCHED IN LIVING CELLS IN REAL TIME. IN PARTICULAR, DR. ROTHMAN HAS HELPED TO ESTABLISH THE SNARE HYPOTHESIS OF MEMBRANE FUSION WHICH PROPOSES THAT THE CORRECT PAIRING OF ALPHA HELICAL PROTEINS ON TWO OPPOSED MEMBRANES DIRECTS AND CATALYZES THEIR FUSION. ALONG WITH THESE IMPORTANT DISCOVERIES DR. ROTHMAN MENTORED AND TRAINED MANY PROMINENT SUCCESSFUL BIOCHEMISTS AND CELL BIOLOGISTS. HE'S A MEMBER OF THE NAB NATIONAL ACADEMY, INSTITUTE OF MEDICINE AND RECIPIENT OF NUMEROUS AWARDS INCLUDING LASTER AWARD FOR BASIC SCIENCE AND CAVALI PRIZE FOR NEUROSCIENCE. HE WILL DISCUSS HIS RECENT WORK ON SNARES AND THE ACCESSORY PROTEINS THAT DIRECT THEIR FUSION. IN A TALK TITLED MOLECULAR MECHANISMS OF SYNCHRONOUS NEUROTRANSMITTER RELEASE. AFTER THE SEMINAR THERE WILL BE A RECEPTION IN THE LIBRARY SO PLEASE COME AND THEY'LL GIVE YOU AN OPPORTUNITY TO SPEAK MORE INFORMALLY WITH DR. ROTHMAN. JOIN ME GIVING A WARM WELCOME TO JIM ROTHMAN. [APPLAUSE] >> THANK YOU. THANKS FOR ARRANGING THE DAY, BEING A GREAT HOST AND ALSO SHARING WITH ME YOUR RECENT AND EXCITING WORK especially on novel methods used Ford measuring confirmational changes in proximity with fret. IT'SER EXCITING, I HOPE WE CAN COLLABORATE AS A RESULT OF THAT. PLEASURE TO BE HERE WITH YOU TODAY. I'M GOING TO AS THE TITLE SUGGESTS, TALK ABOUT THE PROCESS OF SYNCHRONOUS NEUROTRANSMITTER RELEASE. THERE'S BEEN A LOT OF PROGRESS OVER THE LAST FIVE YEARS I WOULD SAY ESPECIALLY IN BEGINNING TO UNDERSTAND THE MECHANISM BY WHICH THIS VERY IMPORTANT PHYSIOLOGICAL PROCESS OCCURS IN STRUCTURAL AND BIOCHEMICAL TERMS. SO WHAT I WOULD LIKE TO DO TODAY IS OFFER SOME HISTORICAL BACKGROUNDS TO THE THE PROBLEMS AND THEN AFTER THAT SHARE WITH YOU OUR CURRENT VIEW IN THE FORM OF A MODEL OF HOW A SYNCHRONOUS TRANSMISSION NEUROTRANSMITTER RELEASE MAY WORK. A STRUCTURAL BUOY CHEMICAL MODEL AND AFTER THAT SHOW YOU SOME OF THE EVIDENCE ACCUMULATED FOR THE MODEL OVER THE LAST TWO OR THREE YEARS ESPECIALLY. WHAT DO I MEAN BY SYNCHRONOUS NEUROTRANSMITTER RELEASE? IT'S ACTUALLY THE PHYSIOLOGISTS HAVE VARIOUS COMPLEX SCHEMES TO MEASURE IT AND WAYS OF DEFINING IT. TO ME IT'S VERY SIMPLE BUT FUNDAMENTAL CONCEPT IN NEUROSCIENCE WHICH IS WHEN THE ACTION POTENTIAL COMES DOWN THE END OF THE NERVE AND YOU RELEASE A NEUROTRANSMITTER ACROSS A SYNAPSE TO THE NEXT NERVE OR PERHAPS MUSCLE CELL, THE NEUROTRANSMITTER NEEDS TO BE RELEASED AT THE RIGHT TIME. WE DIDN'T WANT THE NEUROTRANSMITTER TO BE RELEASED ASYNCHRONOUSLY ON ITS OWN ACCORD BECAUSE IN THAT CASE IT'S A FALSE ALARM. YOU ALSO DON'T WANT THE NEUROTRANSMITTER TO GO NOT BEING RELEASED BECAUSE YOU MISSED AN IMPORTANT SIGNAL. IN FACT WHAT YOU WANT, YOU WANT THE NEUROTRANSMITTER TO BE RELEASED PRECISELY SYNCHRONOUSLY WITH THE ARRIVAL OF ACTION POTENTIAL AT SYNAPTIC TERMINAL. THE WAY THAT'S ACHIEVEED IS THROUGH MEMBRANE GATED CALCIUM CHANNELS, PROBABLY EVERYONE KNOWS THAT ARE LOCALIZED IN THE SYNAPTIC PRE-SYNAPTIC REGION THAT OPENED UP THE GATE FOR CALCIUM ENTRY AND IT ACTS AS A SECOND MESSENGER TO TRIGGER RELEASE OF NEUROTRANSMITTER STORED IN VESICALES. THE PROBLEM THAT WE HAVE TAKEN ON THAT I WOULD LIKE TO ADDRESS HERE IS NUMBER ONE HOW ARE THESE VESICLES RELEASED? HOW DO THEY FUSE WITH THE SURROUNDING MEMBRANE HAVING STORED THE NEUROTRANSMITTER WITHIN THEMSELVES. HOW DO THEY DO IT SO RAPIDLY? SO MUCH MORE RAPIDLY, ORDERS OF THE MAGNITUDE MORE RAPIDLY. THAN OTHER MEMBRANE FUSION PROCESSES THAT TAKE PLACE IN THE CELL. SO THOSE ARE THE ASPECTS BUILT INTO SIN CROW IN THISTY. IT'S OBVIOUSLY IMPORTANT AT A GROSS LEVEL. IN YOUR BRAIN IF YOUR NEUROTRANSMITTERS WERE RELEASED HEALTHER SETTLER, THERE WOULD BE NO POSSIBILITY OF C9 INFORMATION PROCESSING OR ANYTHING OF ANY REMOTE INTEREST. YOU WOULD