Zvi Selinger passed away on September 14, 2008.

Zvi was my mentor. I knew him for more than 15 years, the majority of which I spent in his lab. I was half a world away when I heard of his passing, so I was not at his funeral to say goodbye. Here I want to commemorate this wonderful man, who had a tremendous influence on me and my life.

Zvi Selinger was a great scientist - a brilliant scientist - whose intuition, breadth of knowledge, and keen intellect shone through every time we talked. He is best known for his breakthrough discoveries of the Regulatory GTPase Cycle, the control mechanism for nature's ubiquitous molecular switches - G-proteins. Zvi and Dani Cassel, back in the 1970's, were the first to tease apart the mechanism of how G-proteins really work. Zvi has told me many a story about these times, and of the difficulties they had in publishing their groundbreaking papers (many of which were published in journals that today would be classified as "low impact journals"). Like many of Zvi's stories, there was a moral here - as a scientist you have to do everything you can to validate your results ("controls, controls, controls"). However, Zvi said, once "the story" is there and you know you did a good job, you need to believe in your work despite harsh criticism. As an example, he often quoted the critique that got their first pivotal paper rejected by JBC: "This is prejudice and not science. If the hormone has any effect on the GTPase, it should inhibit rather than stimulate the hydrolysis of GTP." Zvi and Dani replied to the editor that they were not in the business of arguing what the hormone should or should not do, but rather were reporting what the hormone did do. But the paper was nevertheless rejected and was published elsewhere. In a typical Zvi fashion, he was not discouraged by this criticism. On the contrary, it drove him to prove his hypothesis more conclusively, and this turned out to be the first of many papers on this influential theme.

This story and others from that exciting period took place many years before I met Zvi, and are much better described in Zvi's own eloquent words. These stories illuminate a side of Zvi I always admired - he did not believe in taking the easy path. Zvi always sought a new intellectual challenge, always endeavored to learn something new. This is evident in Zvi's exceptionally diverse publication list, which contains papers on G-proteins (of course), neuropeptides, secretion, invertebrate vision, structural studies of proteins and many other key topics. Each of these papers is different, as Zvi was not looking to publish "more of the same". Some more details (in Hebrew) on his scientific interests and achievements can be found in the Israel Prize site and the EMET prize site.

Nevertheless, these scientific works do not truly reveal the Zvi Selinger that I knew. Yes, he was an excellent scientific writer, but Zvi was at his shining best one-on-one. One had to meet Zvi in person to fully appreciate him as a scientist. He was sharp as a razor but unassuming in his demeanor, with a phenomenal depth and breadth of knowledge even on subjects far from his own work. Many visiting scientists were astounded that after talking to Zvi for a while, he would ask them a question they never thought to ask, illuminate a surprising side of their findings, or suggest a new research direction or experiment that was unexpected, but would often lead to breakthrough results. It was a pleasure to talk to him about science, and his encyclopedic scholarship never ceased to amaze me.

Zvi was my mentor, and an outstanding one at that. He practiced the philosophy of "teach a man to fish instead of giving him a fish": he would send me to think about a problem by myself, and then would patiently ask me to explain my reasoning, or play devil's advocate and see if I thought the matter through. If he thought I was wrong, he would wait until I found the holes in my logic, rather than provide me with the answer. Zvi loved the process of working together: asking the questions, designing the experiments, and analyzing the results. He was not overly enthusiastic about teaching large undergraduate classes; he much preferred a more intimate setting and discussing future results, rather than repeating what was already known. What he truly enjoyed was talking to his students about their research, their thoughts, or the new exciting paper he read that day. There were days I spent hours talking to Zvi about work, life, and everything in between. I remember that at times I wished for a little less attention so I would have more time to move ahead with my work. But in retrospect I don't regret a minute of these conversations - Zvi was the best teacher one could hope for and his rich sense of humor made these conversations all the more enjoyable. He expected a lot from his students and would hold them to high standards, but in doing so he was always supportive, encouraging and would never pull rank. I never doubted that Zvi really cared for me as a person, and that even though science ranked above many other things, the people behind the science were even more important. He was not the boss, and the lab did not feel like a work place - the lab was like a family, and Zvi made it feel like home.

Zvi was my role-model, my mentor, and my friend. I will miss him greatly and he will always be in my heart.

Mickey Kosloff (2008).