Postdoctoral Research Scientist
Jovanovic lab
Columbia University
Title: Complex Matters: Studying the Dynamics of Protein Assembly States
Abstract: Studies of proteome dynamics often focus on abundance, yet expression levels alone rarely capture the full picture. Most proteins assemble into higher-order molecular complexes to exert their functions. A protein’s assembly state (for example, whether it is monomeric or integrated into distinct complexes) can shift between biological conditions without changes in expression, with major functional consequences.
To facilitate studies of assembly state dynamics, in my postdoctoral work I developed mass spectrometry-based tools to conduct differential analyses of complex composition and study how incorporation into different assemblies alters protein properties. In my talk I will present two projects. First, the development of SEC-MX, a novel method that enables concomitant measurement of protein assembly states and phosphorylation across conditions. Using this approach, I showed that many proteins are regulated in an assembly state-specific manner, with phosphorylation often confined to particular states. The second project investigates how assembly states affect protein stability. By measuring turnover in vivo in mouse brains and livers with assembly state resolution, I found that some proteins display distinct lifetimes in their monomeric versus assembled forms and explored how these relationships shift with age.
Together, these studies support the idea that a protein’s integration into different complexes can be viewed as generating distinct functional “isoforms”. This perspective provides insights into how proteins are regulated beyond expression levels, with implications for a wide array of biological systems.
Host: Brent Stockwell
