title: Kaposi's sarcoma herpesvirus-encoded latency-associated nuclear antigen stabilizes intracellular activated Notch by targeting the Sel10 protein.
abstract: Deregulation of the evolutionarily conserved Notch signaling is highly correlated with oncogenesis. Intracellular activated Notch (ICN) is a protooncogene linked to the transcription activation of a number of cellular genes involved in cell cycle regulation, differentiation, and proliferation. Stability of ICN is tightly regulated by the Sel10-mediated ubiquitin-proteasome pathway. Sel10 can function as a negative regulator of Notch and exhibits activities of a tumor-suppressor protein. This article shows that the Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) directly interacts with Sel10 and forms a complex in KSHV-infected cells. This results in suppression of ICN ubiquitination and degradation. The carboxyl terminus of LANA interacts with the F-box and WD40 domains of Sel10 and competes with ICN for binding to Sel10. This elevated level of ICN is also critical for maintaining the enhanced proliferation of KSHV-infected tumor cells. These findings describe a mechanism by which the KSHV-encoded LANA protein regulates ubiquitination of ICN mediated by the F-box component of the E3 ligase Sel10, leading to proliferation of the virus-infected cells.
authors.affiliation: Department of Microbiology and Tumor Virology Program of Abramson Comprehensive Cancer Center, University of Pennsylvania Medical School, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Lan
authors.forename: Subhash C
authors.initials: SC
authors.lastname: Verma
authors.forename: Masanao
authors.initials: M
authors.lastname: Murakami
authors.forename: Bharat
authors.initials: B
authors.lastname: Bajaj
authors.forename: Rajeev
authors.initials: R
authors.lastname: Kaul
authors.forename: Erle S
authors.initials: ES
authors.lastname: Robertson
mesh_terms: D000956:Antigens, Viral / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D049109:Cell Proliferation; D002472:Cell Transformation, Viral; D044783:F-Box Proteins / Q000737:chemistry / Q000378:metabolism*; D000073979:F-Box-WD Repeat-Containing Protein 7; D019288:Herpesvirus 8, Human / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D006801:Humans; D008954:Models, Biological; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011519:Proto-Oncogenes; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D000956:Antigens, Viral; D018797:Cell Cycle Proteins; D044783:F-Box Proteins; D000073979:F-Box-WD Repeat-Containing Protein 7; C513273:FBXW7 protein, human; D009687:Nuclear Proteins; D051880:Receptors, Notch; C109540:latency-associated nuclear antigen; D044767:Ubiquitin-Protein Ligases