SP1 and viral infectious disease: Four-and-a-half LIM domain protein 1 (FHL1) ismostly involved in muscle function and development but has been shownto play a key role in chikungunya virus infection via interactionwith nsP3. FHL1 also has a well-knownrole in activating ERK1/2 signaling through interaction with transcriptionfactor SP1 and through direct interactionwith ERK1/2 signaling components. Furtherinvestigation into the roles of SARS-CoV-2 and SARS-CoV nsp15 in ERK1/2signaling may reveal key regulatory mechanisms during viral infection.