Protein subinteractomes of human microsomal cytochromes P450

Area of Science:

• Biochemistry
• Systems Biology
• Molecular Biology

Background:

• Microsomal cytochromes P450 (micCYPs) are key enzymes in drug and endogenous substrate metabolism, primarily located in the endoplasmic reticulum.
• Their known function involves electron transfer from redox partners for enzymatic transformations.
• The extensive diversity of micCYPs suggests potential for interactions beyond these classical partners.

Purpose of the Study:

• To conduct a systems biology analysis of all known protein-protein interactions (PPIs) for 33 human micCYPs.
• To examine the specific protein interaction networks (subinteractomes) for each micCYP.
• To explore the functional implications of these interactions beyond canonical metabolic roles.

Main Methods:

• Retrieval of 287 PPIs from interactomic databases for 33 human micCYPs.
• Analysis of protein interactor characteristics, including subcellular localization and functional pathways.
• Integration of transcriptomic data to assess tissue-, time-, and disease-specific expression patterns of micCYP/interactor pairs.

Main Results:

• Identified 287 PPIs involving 246 unique protein interactors, many sharing subcellular localization with micCYPs.
• Interactors are involved in diverse cellular processes: metabolism, signal transduction, cell junctions, cytoskeleton, and transport.
• A significant portion of interactors are membrane transporters; specific micCYPs show enrichment in pathways like autophagy and signaling (e.g., CYP2C8, CYP2S1, CYP3A4).
• Identified common interactors (UBC, PGRMC1, FANCG) and potential direct CYP-CYP interactions.
• Transcriptomic analysis revealed specific expression patterns for certain micCYP/interactor pairs, influenced by drugs.

Conclusions:

• Microsomal cytochromes P450 engage in a wide array of protein-protein interactions, extending beyond their established redox partners.
• These interactions suggest novel roles for micCYPs in cellular transport, signaling, and other functions.
• The findings highlight the importance of considering the broader interactome for understanding micCYP biology and drug effects.