CBE/ENGR 225 Seminar Presents: Joao Hespanha, Ph.D., Professor Professor and Chair, Dept. of Electrical & Computer Engineering, Dept. of Mechanical Engineering and Center for Control, Dynamical-systems, and Computation, UCSB
Joao Hespanha, Ph.D.
Professor and Chair, Dept. of Electrical & Computer Engineering,
Dept. of Mechanical Engineering and Center for Control, Dynamical-systems, and Computation
University of California, Santa Barbara
Tuesday, February 7, 2017
ESB, Room #2001
*Cookies and Coffee will be provided*
A Modular Perspective on the Evolution of the p53 Network
Abstract: The p53 is a tumor suppressor gene that is known to be a central hub of the DNA damage response
network. It plays a critical role in guarding against cancer development and the loss of p53 function is involved in
most human cancers.
In humans, p53 is part of a sophisticated network of proteins that mediate cell fate decisions such as the
initiation of cell-cycle arrest, DNA repair, senescence and apoptosis. Aside from p53, this network includes the
proteins MDM2, PTEN, and ARF among a host of other upstream, downstream and intermediate species
involved in sensing, transduction and regulation.
In this talk we explore the evolutionary history of the p53 protein network. While homologs of the p53 gene
seem to have been preserved over one billion years, this is not the case for the other proteins in the network;
one can find organisms that express a p53 homolog together with different combinations of the remaining
We use the evolutionary analysis as the starting point to partition the p53 network into independent modules
and then attempt to infer the function of each module within the network. Our results show an evolutionary path
towards networks with an increasingly complex structure of multi-stability, which we conjecture is associated
with cell fate decisions.
(*) Work done in collaboration with Hari Sivakumar and Stephen Proulx.