Tyrosine kinase SYK (spleen tyrosine kinase), an enzyme involved in immune signaling, could play a key role in Alzheimer's disease (AD), multiple sclerosis (MS), and other neurodegenerative diseases, according to a study from the University of Virginia (UVA). SYK regulates the activity of microglia, preventing the accumulation of secretions associated with AD or MS produced in these pathologies.