| Citation | Jonathan Pines is recognized for his seminal work in cloning mammalian cyclins, which in complex with cyclindependent kinases regulate cell cycle progression. His demonstration that cyclins A and B are regulated through differential cellular localization, with cyclin B being held out of the nucleus until the start of mitosis, provided a key new cell cycle regulatory principle. He pioneered the use of GFP-tagged cell cycle proteins to study their localization in living cells, showing that cyclin B1-Cdk1 activation is spatially regulated, and to determine the precise timing and mechanism of their destruction in the mitotic phase of the cell cycle. |