All storytellers want to tell their story all the way to its end. Imagine how unsatisfying most movies or books would be without their endings. What if Scout didn’t get to meet Boo Radley? How boring would The Sixth Sense be? How tragic would Toy Story 3 be?! In cell biology, telling a whole story in one paper, from protein to cell to animal, is a rare luxury given the time and difficulty of most techniques. Today’s image is from a paper with a well-rounded story about the role of a cell cycle protein in non-cell cycle-related business.
The cell cycle is driven forward by complexes made up of proteins called cyclins and cyclin-dependent kinases (Cdks). One cyclin called cyclin E functions in the G1 to S phase transition in the cell cycle, marking the start of DNA replication. Because of this role, cyclin E is typically found in only dividing cells. A recent paper describes the important role of cyclin E in non-dividing cells in the adult brain. In this paper, Odajima and colleagues found that cyclin E regulates synapse formation by inhibiting Cdk5. Cyclin E disruption in neurons causes the number of synapses and dendritic spines to drop. Finally, adult mice with cyclin E-deficient brains had impaired learning and memory. In the images above, non-dividing neurons from mouse brain show the presence of cyclin E (red) in both axons and dendrites, along with Cdk5. SynGAP and Synapsin I are post- and presynaptic markers.
Odajima, J., Wills, Z., Ndassa, Y., Terunuma, M., Kretschmannova, K., Deeb, T., Geng, Y., Gawrzak, S., Quadros, I., Newman, J., Das, M., Jecrois, M., Yu, Q., Li, N., Bienvenu, F., Moss, S., Greenberg, M., Marto, J., & Sicinski, P. (2011). Cyclin E Constrains Cdk5 Activity to Regulate Synaptic Plasticity and Memory Formation Developmental Cell, 21 (4), 655-668 DOI: 10.1016/j.devcel.2011.08.009
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