This proposal focuses on studying the molecular mechanisms of nuclear insulin signaling. Insulin-responsive trans-acting nuclear proteins binding to the human growth hormone promoter will be sought in insulin treated cells utilizing a mobility shift assay. Nucleotides important for the observed binding activity will be identified and the insulin-responsive DNA-binding protein characterized. Preliminary data identifies an insulin-induced trans-acting factor which binds to the GH promoter in a sequence specific manner. The functional role of the identified insulin-responsive DNA-binding proteins will be tested by in vitro mutagenesis and transient transfection experiments. Candidate: The P.I. has a sound clinical training and has acquired the necessary molecular techniques to answer fundamental questions as a physician-scientist in an academic environment. The environment: The proposed studies will be performed in the well equipped laboratory of the sponsor from whom the applicant has received excellent training and guidance in the past. The applicant will also be exposed to senior researchers in areas of pituitary gene expression and tumorigenesis, diabetes, bone and vitamin D metabolism, lipids, placental proteins and thyroid tumorigenesis. Significance: This project will provide insight into the mechanisms of nuclear insulin signaling and in the long term will enhance our understanding of insulin regulation of cellular proteins as well as specific gene expression. This will provide fundamental information on the mechanism of insulin action and the pathogenesis of complications found in clinical states of insulin deprivation or attenuated insulin action. This award will afford the applicant an opportunity to develop as an independent clinical investigator.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08DK002023-04
Application #
2133686
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Project Start
1991-07-01
Project End
1996-06-30
Budget Start
1994-08-01
Budget End
1995-06-30
Support Year
4
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Cedars-Sinai Medical Center
Department
Type
DUNS #
075307785
City
Los Angeles
State
CA
Country
United States
Zip Code
90048
Pei, L; Melmed, S; Scheithauer, B et al. (1995) Frequent loss of heterozygosity at the retinoblastoma susceptibility gene (RB) locus in aggressive pituitary tumors: evidence for a chromosome 13 tumor suppressor gene other than RB. Cancer Res 55:1613-6
Greenman, Y; Prager, D; Melmed, S (1995) The IGF-I receptor sub-membrane domain is intact in GH-secreting pituitary tumours. Clin Endocrinol (Oxf) 42:169-72
Webster, J; Prager, D; Melmed, S (1994) Insulin-like growth factor-1 activation of extracellular signal-related kinase-1 and -2 in growth hormone-secreting cells. Mol Endocrinol 8:539-44
Pei, L; Melmed, S; Scheithauer, B et al. (1994) H-ras mutations in human pituitary carcinoma metastases. J Clin Endocrinol Metab 78:842-6
Prager, D; Li, H L; Asa, S et al. (1994) Dominant negative inhibition of tumorigenesis in vivo by human insulin-like growth factor I receptor mutant. Proc Natl Acad Sci U S A 91:2181-5
Prager, D; Li, H L; Yamasaki, H et al. (1994) Human insulin-like growth factor I receptor internalization. Role of the juxtamembrane domain. J Biol Chem 269:11934-7
Prager, D; Yamasaki, H; Weber, M M et al. (1994) Role of the insulin-like growth factors in regulating neuroendocrine function. Neurobiol Aging 15:569-72
Ejima, E; Rosenblatt, J D; Massari, M et al. (1993) Cell-type-specific transactivation of the parathyroid hormone-related protein gene promoter by the human T-cell leukemia virus type I (HTLV-I) tax and HTLV-II tax proteins. Blood 81:1017-24
Yamamoto, H; Prager, D; Yamasaki, H et al. (1993) Rat pituitary GC cell insulin-like growth factor-I receptor regulation. Endocrinology 133:1420-5
Prager, D; Weber, M M; Gebremedhin, S et al. (1993) Interaction between insulin and thyroid hormone in rat pituitary tumour cells: insulin attenuates tri-iodothyronine-induced growth hormone mRNA levels. J Endocrinol 137:107-14

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