title: Identification and characterization of a novel folliculin-interacting protein FNIP2.
abstract: Birt-Hogg-Dube' syndrome characterized by increased risk for renal neoplasia is caused by germline mutations in the BHD/FLCN gene encoding a novel tumor suppressor protein, folliculin(FLCN), which interacts with FNIP1 and 5'-AMP-activated protein kinase(AMPK). Here we report the identification and characterization of a novel FNIP1 homolog FNIP2 that also interacts with FLCN and AMPK. C-terminally-deleted FLCN mutants, similar to those produced by naturally-occurring germline mutations in BHD patients, were unable to bind FNIP2. These data taken together with our previous results that demonstrated FNIP1 binding to the C-terminus of FLCN suggest that FLCN tumor suppressor function may be facilitated by interactions with both FNIP1 and FNIP2 through its C-terminus. Furthermore, we demonstrate that FNIP1 and FNIP2 are able to form homo- or heteromeric multimers suggesting that they may function independently or cooperatively with FLCN. Differential expression of FNIP1 and FNIP2 transcripts in some normal tissues may indicate tissue specificity for these homologs. Interestingly FNIP1 and FNIP2 were oppositely expressed in human clear cell renal cell carcinoma (RCC), and coordinately expressed in chromophobe RCC and oncocytoma, suggesting their differential function in different histologic variants of RCC.
authors.affiliation: Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20894, United States.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hasumi
authors.forename: Masaya
authors.initials: M
authors.lastname: Baba
authors.forename: Seung-Beom
authors.initials: SB
authors.lastname: Hong
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Hasumi
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yao
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Valera
authors.forename: W Marston
authors.initials: WM
authors.lastname: Linehan
authors.forename: Laura S
authors.initials: LS
authors.lastname: Schmidt
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D000595:Amino Acid Sequence; D002292:Carcinoma, Renal Cell / Q000235:genetics; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D019143:Evolution, Molecular; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D007680:Kidney Neoplasms / Q000235:genetics; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013347:Subcellular Fractions / Q000201:enzymology; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; C476078:FLCN protein, human; C516440:FNIP1 protein, human; C529782:FNIP2 protein, human; D046912:Multiprotein Complexes; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; D000263:Adenylate Kinase