title: Transcriptional regulation of PEN-2, a key component of the gamma-secretase complex, by CREB.
abstract: Gamma-secretase, which is responsible for the intramembranous cleavage of Alzheimer's beta-amyloid precursor protein (APP), the signaling receptor Notch, and many other substrates, is a multiprotein complex consisting of at least four components: presenilin (PS), nicastrin, APH-1, and PEN-2. Despite the fact that PEN-2 is known to mediate endoproteolytic cleavage of full-length PS and APH-1 and nicastrin are required for maintaining the stability of the complex, the detailed physiological function of each component remain elusive. Unlike that of PS, the transcriptional regulation of PEN-2, APH-1, and nicastrin has not been investigated. Here, we characterized the upstream regions of the human PEN-2 gene and identified a 238-bp fragment located 353 bp upstream of the translational start codon as the key region necessary for the promoter activity. Further analysis revealed a CREB binding site located in the 238-bp region that is essential for the transcriptional activity of the PEN-2 promoter. Mutation of the CREB site abolished the transcriptional activity of the PEN-2 promoter. Electrophoretic mobility shift assays and chromatin immunoprecipitation analysis showed the binding of CREB to the PEN-2 promoter region both in vitro and in vivo. Activation of the CREB transcriptional factor by forskolin dramatically promoted the expression of PEN-2 mRNA and protein, whereas the other components of the gamma-secretase complex remained unaffected. Forskolin treatment slightly increases the secretion of soluble APPalpha and Abeta without affecting Notch cleavage. These results demonstrate that expression of PEN-2 is regulated by CREB and suggest that the specific control of PEN-2 expression may imply additional physiological functions uniquely assigned to PEN-2.
authors.affiliation: National Laboratory of Medical Genetics of China, Xiang-Ya Hospital, Central South University, 410078 Changsha, Hunan, China.
authors.forename: Ruishan
authors.initials: R
authors.lastname: Wang
authors.forename: Yun-wu
authors.initials: YW
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Sun
authors.forename: Runzhong
authors.initials: R
authors.lastname: Liu
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.forename: Xue
authors.initials: X
authors.lastname: Zhang
authors.forename: Kun
authors.initials: K
authors.lastname: Xia
authors.forename: Jiahui
authors.initials: J
authors.lastname: Xia
authors.forename: Huaxi
authors.initials: H
authors.lastname: Xu
authors.forename: Zhuohua
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D003001:Cloning, Molecular; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D010450:Endopeptidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D053764:Presenilin-1; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; D008565:Membrane Proteins; D046912:Multiprotein Complexes; C508853:PSEN1 protein, human; C469349:PSENEN protein, human; D053764:Presenilin-1; D012333:RNA, Messenger; D004247:DNA; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human