GPBP1 (GC-rich promoter binding protein 1) functions as a transcription factor with dual nucleic acid binding capabilities. As a DNA-binding transcription factor, GPBP1 acts as a GC-rich promoter-specific transactivator regulating DNA-templated transcription in the nucleus 1. Beyond canonical DNA binding, GPBP1 contains an extended AT-hook motif that binds RNA with approximately tenfold higher affinity than DNA, suggesting roles in RNA-dependent cellular processes 1. Cytoplasmic GPBP1 exhibits broader regulatory functions. It serves as a non-conventional Ser/Thr kinase that directs myofibril formation by targeting GIP130, a myosin-binding protein that promotes myofibrillar assembly 2. In kidney physiology, GPBP1 interacts with RTN3 to activate the IGF2-JAK2-STAT3 pathway, regulating collagen biosynthesis and mitochondrial function 3. Clinically, GPBP1 loss confers resistance to cisplatin and PARP inhibitors in cancer cells through dysregulation of homologous recombination genes, representing a significant mechanism of chemotherapy resistance 4. Additionally, GPBP1 reduced expression associates with chr5 kidney disease and kidney fibrosis, identifying it as a potential risk factor for renal pathology 3. These findings establish GPBP1 as a multifunctional regulator linking transcriptional control to protein assembly and DNA damage responses.