Identification of phosphorylation site on PARP1 mediating its cytosolic translocation in virus-infected HeLa cells

Poly (ADP-ribose) polymerase 1 (PARP1) localization is controlled by its phosphorylation state. Here, we describe a protocol to monitor PARP1 subcellular localization in HSV-1-infected HeLa cells using immunofluorescence microscopy and cytoplasmic/nuclear fractionation. We detail steps to identify phosphorylation sites on PARP1 using conserved motif analysis and mass spectrometry. This protocol can be applied to the study of other protein phosphorylation events in other cell types. For complete details on the use and execution of this protocol, please refer to Wang et al. (2022).