Mark S. Johnson

Mark S. Johnson, PhD, is an Associate Professor in the Department of Basic Sciences, Microbiology Division, School of Medicine at Loma Linda University. His primary research focuses on bacterial signal transduction mechanisms, particularly the structural and functional aspects of PAS-domain proteins involved in oxygen sensing and aerotaxis. He has authored over 50 peer-reviewed publications and contributed to books in the field of bacterial physiology and molecular microbiology.

Education:

• PhD in Microbiology, University of Utah (1984)
• BA in Biology, North Park University (1973)

Research Interests: Dr. Johnson’s work centers on understanding how bacteria sense and respond to environmental signals, specifically oxygen and redox conditions. Key areas include:

• PAS domain structure-function relationships
• Protein domain interactions in chemoreceptors
• Oxygen-dependent behavior in pathogenic and non-pathogenic bacteria
• Signal transduction pathways in aerotaxis systems

Recent Research Trends: His recent studies (2018–2021) highlight advancements in understanding the PAS-heme domain of Aer2 receptors in Pseudomonas aeruginosa and Vibrio cholerae, elucidating oxygen-sensing mechanisms and conformational changes. Collaborations with colleagues like Kylie Watts and Barry Taylor have produced insights into domain interactions and signaling pathways.

Labs/Teams: He is part of interdisciplinary teams investigating bacterial physiology, with a focus on structural biology and molecular mechanisms of bacterial sensing systems.