The major research interests of Dr. Kalvakolanu's lab are regulation of gene transcription and signal transduction by cytokines; Tumor cell growth control; and Regulation of novel Cell death-activating genes. Cell death via apoptosis is central to vertebrate development, pathogenesis and immunoregulation. Too much apoptosis in neurodegenerative diseases and too little of it in cancers have been documented. Dr. Kalvakolanu's laboratory currently studies the regulation of apoptosis by Interferons and vitamin A metabolites in human tumor cells. The IFN/RA combination induces apoptosis in a variety of tumor cells in vitro and in vivo. To identify the players in this pathway, this laboratory has applied a genetic technique, the Suppression of Mortality by Antisense-Rescue Technique (SMART) or Antisense technical knockout. The application of this method led to the identification of several novel "Genes-associated with Retinoid- Interferon induced Mortality (GRIM). This laboratory is currently focused on the regulation of GRIM-19, a novel death gene. GRIM-19 seems to interact with number multiprotein complexes within the cells as evidenced by punctate immunocytochemical staining patterns and by protein interaction strategies. Subsequent to our discovery other groups have shown that GRIM-19 is part of complex-I of mitochondrial electron transport chain. We have recently shown that viral oncogenes such the vIRF1 of Kaposi's sarcoma associated HHV8 and HPV-E6 oncogene inhibit its apoptotic functions to promote cell survival and tumor growth. We have also shown that GRIM-19 acts as a specific inhibitor of STAT3, whose constitutive activity has been shown in a number of human cancers. More recently our studies with clinical tumors have documented a loss of the GRIM-19 expression in a number of human cancers. Some esophageal and colon cancers express an anti-apoptotic inhibitor of GRIM-19. Mechanism of action of GRIM-19 and other novel death genes in the regulation of apoptosis is being investigated using knockout and cell line models. In another study, our lab also identified earlier a novel IFN-g responsive element, called GATE. Our subsequent studies identified that the b-ZIP transcription factor C/EBP-b plays a critical role in regulating transcription through this element. C/EBP-b is also essential for cell differentiation, metabolic gene expression, and macrophage-dependent anti-tumor and anti-pathogen defenses. Recently, we have established bonemarrow macrophage cell lines lacking C/EBP-b and performed a gene expression profiling to identify the IFN-regulated genes dependent on C/EBP-b for their transcription. Several genes involved in growth control, immune response and cell signaling have been identified in these studies. Similarly we have initiated another study to identify the proteins modify C/EBP-b's transcriptional activity in response to IFN-g in macrophages, using proteomic approaches. These studies have identified several interesting proteins, including a novel protein kinase, which specifically associates with C/EBP-b. We are currently investigating the role of this new protein kinase in IFN and other cytokine signal transduction pathways.