There are many ways to measure a musician's progress, and the instrument he or she plays is positively one of them. "As a boy I hated practicing, and I remember throwing the cello case - with the cello in it - into the air on my way to music school one day. To my regret, the cello was repaired very soon - and this simple factory-made instrument sounded even better," recollects Israeli cellist Kyril Zlotnikov, speaking over the phone from his home in Lisbon. Zlotnikov, 31, will participate in various programs of the Jerusalem International Chamber Music Festival, which runs August 31 to September 12 at the capital's YMCA. He will perform as a member of the Jerusalem String Quartet and as a soloist. Though today he plays a cello that once belonged to legendary British cellist Jaqueline du PrÃ© and he loves his instrument passionately, it was a long road getting there. Born in Minsk, Belorussia into a family of musicians, Zlotnikov studied cello and piano from the age of six, and he has nothing but praise for his teacher, Vladimir Perlin. "For a beginner cellist he was excellent; he knew how to ignite a love for music, he made us learn poetry by heart, he discussed literature and painting with us - all in order to develop our creativity, to bring life into our music making. Since he never emigrated from the USSR his name is almost unknown, although he taught many fine musicians. And of course I owe my cellist mother a lot - she made me practice." Upon immigrating to Israel at the age of 13, Zlotnikov auditioned for an America-Israel Cultural Foundation scholarship three days after arrival, and won it. He studied at the Jerusalem Conservatory with Uzi Vizel, Hillel Zori and finally with the late Michael Homizer. And he was at the Conservatory when the Jerusalem String Quartet was inaugurated. "We were all 15 years old - violist Amichai Grosz, violinists Alexander Pavlovsky and Sergei Bressler and I. After a few rehearsals, it was already obvious that we could play together," recollects Zlotnikov. "Avi Abramovich, an experienced chamber musician, was our tutor, and he was really good. We performed in various concerts, participated in various master classes." The quartet's real international career started about three years later, when its members studied with the legendary British Amadeus Quartet. After performing at a students' concert, they were invited to give an evening concert at Wigmore Hall. "I'm not sure it has ever happened before - as a trial run, young musicians [normally] perform at daytime concerts first." Zlotnikov says that "playing in a quartet is very much like being married to a quartet. It is a family, we have already spent 16 years together, and yes, we need some breaks from each other - which is also very important. Of course we argue sometimes, but we know how to settle our 'musical conflicts' fast, and this is a good sign." AS A son of a cellist, Zlotnikov did not have much choice in instruments. But today, "cello is the love of my life, it is a part of myself. The cello's possibilities are limitless and if it is good and is played well, it can squeeze a tear even from a log of wood," he smiles. Zlotnikov received his current instrument on loan from Israeli pianist and conductor Daniel Barenboim. "We met first in 2000 at the Jerusalem International Festival of Chamber Music, directed by his wife, pianist Elena Bashkirova. There, we befriended each other. A few months later, he invited me to participate in his project for Arab and Israeli musicians - West-Eastern Divan. I remember him saying one day that he probably has a fine instrument for me, which actually did not surprise me - in those days I played on just a piece of wood. But when he said that he wanted to loan me the cello of his late first wife Jacqueline du PrÃ©, I sat with my mouth wide open for at least half an hour," recollects Zlotnikov. "This was her favorite instrument, which she played the last seven years of her performing career, aside from her two Stradivaris." Zlotnikov revealed that when he received the cello from the famous violin maker Etienne Vatelot, who had kept it, "the instrument did not sound at all! It had not been played for at least two years and it had fallen down into a slumber." It took him a month of intensive playing to "wake it up. To keep an instrument alive, one needs to play it all the time, to feed it with your love. Du PrÃ©'s is a very powerful instrument and I feel that she has breathed her energy into it." Zlotnikov divides his time between the Jerusalem String Quartet - one of the world's leading groups of its kind, which gives about 60 to 70 concerts a year - and his independent career as a chamber and solo cellist. Being an Israeli musician, especially as a member of a quartet whose name is so closely associated with the State of Israel, is not always simple, says Zlotnikov. "Various self-proclaimed pro-Palestinian support groups call for boycotting our concerts, especially in England. Characteristically enough, they do not bother to disturb us when we appear in small towns with almost no chance of press coverage, but they threaten to disrupt our performances at major venues, such as the BBC Proms festival. "On one such occasion, the widow of the late Edward Said, Barenboim's close friend and partner in peace activism, tried to intervene, explaining that two of the Quartet members participate in the East-Western Divan project - but it didn't stop them. I am not afraid for myself, but the very thought that these people are able to throw something onstage and ruin the instruments is really scary." For the detailed Jerusalem International Chamber Music Festival program, visit www.jcmf.org.il. For reservations, call (02) 625-0444.