nanos regulatory sequences drive expression of a transcript that encodes two open reading frames separated by a T2A linker (this results in separate translation of each protein). The first ORF encodes the 'modERK-KTR' kinase translocation reporter of MAPK activity. The 'modERK-KTR' reporter is composed of an ERK docking site fused to Clover with phosphorylation-sensitive NLS and NES signals that result in the protein relocating from the nucleus to the cytoplasm in response to MAPK phosphorylation. 'modERK-KTR' is similar to the 'ERK-KTR' reporter from PMID:24949979, but it has been modified to be more specific to ERK. The second ORF encodes His2Av tagged with mCherry, a red fluorescent nuclear marker that can be used as a normalization reference.