RNA-binding subunit of the trimeric nuclear exosome targeting (NEXT) complex, a complex that functions as an RNA exosome cofactor that directs a subset of non-coding short-lived RNAs for exosomal degradation. NEXT is involved in surveillance and turnover of aberrant transcripts and non-coding RNAs. Binds preferentially polyuridine sequences and associates with newly synthesized RNAs, including pre-mRNAs and short-lived exosome substrates such as promoter upstream transcripts (PROMPTs), enhancer RNAs (eRNAs), and 3'-extended products from small nuclear RNAs (snRNAs). Participates in several biological processes including DNA damage response (DDR) and stress response. During stress response, activation of the p38MAPK-MK2 pathway decreases RBM7-RNA-binding and subsequently the RNA exosome degradation activities, thereby modulating the turnover of non-coding transcriptome. Participates in DNA damage response (DDR), through its interaction with MEPCE and LARP7, the core subunits of 7SK snRNP complex, that release the positive transcription elongation factor b (P-TEFb) complex from the 7SK snRNP. In turn, activation of P-TEFb complex induces the transcription of P-TEFb-dependent DDR genes to promote cell viability. Component of the nuclear exosome targeting (NEXT) complex composed of MTREX, ZCCHC8, and RBM7 that directs a subset of non-coding short-lived RNAs for exosomal degradation (PubMed:25525152). Interacts with ZCCHC8 and SF3B2/SAP145. Binds to MTREX through ZCCHC8. Interacts with YWHAE and YWHAZ; these interactions are stress-dependent and RBM7 phosphorylation dependent; release RNA from the NEXT complex and may affect RNA targeting to the nuclear RNA exosomome for degradation. Interacts with MEPCE and LARP7, the core subunits of 7SK snRNP; upon genotoxic stress this interaction is enhanced, triggering the release of inactive P-TEFb complex from the core and P-TEFb complex activation (By similarity). Excluded from the nucleolus. The RRM domain mediates RNA binding; the RNA must have four nucleotides for efficient binding. Mediates the interaction of NEXT complex with promoter upstream transcripts (PROMPTs) and potentially aberrant forms of other non coding RNAs, such as snRNAs. The RRM domain exhibits specificity for polyuridine sequences. Phosphorylated at Ser-136 by MAPK14/p38-alpha-activated MAPKAPK2/MK2; this phosphorylation is stress-dependent; this phosphorylation decreases its RNA-binding capacity therefore affecting RNA nuclear exosome-mediated degradation (PubMed:25525152). This phosphorylation mediates YWHAE and YWHAZ interactions (By similarity).