Epidermal growth factor (EGF) triggers nuclear calcium signaling through the intranuclear phospholipase Cδ-4 (PLCδ4)

• Published in: The Journal of biological chemistry Vol. 294; no. 45; pp. 16650 - 16662
• Main Authors: de Miranda, Marcelo Coutinho, Rodrigues, Michele Angela, de Angelis Campos, Ana Carolina, Faria, Jerusa Araújo Quintão Arantes, Kunrath-Lima, Marianna, Mignery, Gregory A., Schechtman, Deborah, Goes, Alfredo Miranda, Nathanson, Michael H., Gomes, Dawidson A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 08-11-2019; American Society for Biochemistry and Molecular Biology
• Subjects: calcium; calcium intracellular release; Calcium Signaling - drug effects; Cell Line; Cell Nucleus - metabolism; Cell Proliferation - drug effects; Clathrin Heavy Chains - antagonists & inhibitors; Clathrin Heavy Chains - genetics; Clathrin Heavy Chains - metabolism; Cyclin A - metabolism; Cyclin B1 - metabolism; EGFR; Epidermal Growth Factor - pharmacology; epidermal growth factor receptor (EGFR); ErbB Receptors - metabolism; Humans; Hydrolysis; inositol 1,4,5-trisphosphate (IP3); Inositol 1,4,5-Trisphosphate - metabolism; nucleus; Phosphatidylinositol 4,5-Diphosphate - metabolism; phospholipase C; Phospholipase C delta - antagonists & inhibitors; Phospholipase C delta - genetics; Phospholipase C delta - metabolism; Phospholipase C gamma - antagonists & inhibitors; Phospholipase C gamma - genetics; Phospholipase C gamma - metabolism; phospholipase Cδ-4; proliferation; protein kinase C (PKC); Protein Kinase C - metabolism; RNA Interference; RNA, Small Interfering - metabolism; Signal Transduction; phospholipase C; inositol 1,4,5-trisphosphate (IP3); calcium; proliferation; epidermal growth factor receptor (EGFR); protein kinase C (PKC); calcium intracellular release; nucleus; phospholipase Cδ-4; EGFR
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.RA118.006961

Calcium (Ca2+) signaling within the cell nucleus regulates specific cellular events such as gene transcription and cell proliferation. Nuclear and cytosolic Ca2+ levels can be independently regulated, and nuclear translocation of receptor tyrosine kinases (RTKs) is one way to locally activate signaling cascades within the nucleus. Nuclear RTKs, including the epidermal growth factor receptor (EGFR), are important for processes such as transcriptional regulation, DNA-damage repair, and cancer therapy resistance. RTKs can hydrolyze phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) within the nucleus, leading to Ca2+ release from the nucleoplasmic reticulum by inositol 1,4,5-trisphosphate receptors. PI(4,5)P2 hydrolysis is mediated by phospholipase C (PLC). However, it is unknown which nuclear PLC isoform is triggered by EGFR. Here, using subcellular fractionation, immunoblotting and fluorescence, siRNA-based gene knockdowns, and FRET-based biosensor reporter assays, we investigated the role of PLCδ4 in epidermal growth factor (EGF)-induced nuclear Ca2+ signaling and downstream events. We found that EGF-induced Ca2+ signals are inhibited when translocation of EGFR is impaired. Nuclear Ca2+ signals also were reduced by selectively buffering inositol 1,4,5-trisphosphate (InsP3) within the nucleus. EGF induced hydrolysis of nuclear PI(4,5)P2 by the intranuclear PLCδ4, rather than by PLCγ1. Moreover, protein kinase C, a downstream target of EGF, was active in the nucleus of stimulated cells. Furthermore, PLCδ4 and InsP3 modulated cell cycle progression by regulating the expression of cyclins A and B1. These results provide evidence that EGF-induced nuclear signaling is mediated by nuclear PLCδ4 and suggest new therapeutic targets to modulate the proliferative effects of this growth factor.