REGULATION OF CULLIN E3 UBIQUITIN LIGASES BY THE UBIQUITIN LIKE PROTEIN NEDD8 AND CULLIN- INTERACTING PROTEINS BOH BOON KIM B.Sc. (Honors with Distinction), University of Malaya A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY NUS GRADUATE SCHOOL FOR INTEGRATIVE SCIENCES AND ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE (Defended April 26, 2012)