Mehdi Bouhaddou is an Assistant Professor in the Department of Microbiology, Immunology, and Molecular Genetics and co-affiliated with the Institute for Quantitative and Computational Biosciences at UCLA.

Dr. Bouhaddou directs a Quantitative Systems Biology lab that studies how protein-protein interactions and post-translational modifications impact signaling networks, from systems-level features to basic mechanisms. The lab is half “wet” and half “dry”, cultivating an interactive exchange between experimental and computational workflows. Experimentally, his group focuses on global mass spectrometry proteomics, affinity purification mass spectrometry (APMS), cell culture-based virology, genetic perturbation screens, pharmacology, and molecular biology. Computationally, they specialize in bioinformatics, network modeling, and ordinary differential equation (ODE) modeling.

Cellular signaling networks, governed by protein phosphorylation, encode how cells sense and respond to their environment. Phosphoproteomics enables a global, biology-agnostic snapshot of these networks, providing a direct readout of pathway activity beyond gene or protein abundance.

Dr. Bouhaddou's work studies phosphorylation across biological taxa. First, his group maps how viral phosphorylation events alter viral fate decisions in a cellular context-dependent manner. Second, they define the mechanisms by which environmental exposures, such as wildfire smoke and firefighter personal protective equipment (PPE), disrupt airway epithelial signaling and firefighter health. Third, they extend these approaches to coral symbiosis to reveal how signaling remodeling shapes host–symbiont interactions and regulates coral resilience to heat stress. Together, they aim to establish phosphoproteomics as a unifying strategy to decode the biochemical logic of disease across taxa—from viruses to humans to ecosystems—highlighting conserved principles of signaling regulation and identifying new therapeutic and environmental interventions.