Follistatin-related protein (FSRP) is a recently discovered glycoprotein whose gene structure and activin binding properties are highly homologous to the activin binding protein follistatin (FS). FSRP was originally cloned as an overexpressed protein in a B-cell leukemia and is expressed in numerous cancer cell lines, suggesting it may be involved with, or be a useful marker for a wide array of tumors. Unlike FS, however, FSRP is most highly expressed in the placenta and testis (FS is highest in the ovary and kidney), indicating that FSRP has unique functions in these tissues. Immunocytochemical studies have demonstrated that FSRP is highly concentrated in the nucleus of all cell lines and primary cells tested, but is secreted only by cells with the highest FSRP expression levels. These observations suggest that regulation of FSRP intracellular trafficking is complex and unique, and further, that FSRP may have nuclear activities distinct from strictly non-nuclear FS. Overexpression of FSRP in transgenic mice disrupts follicular development, resulting in female infertility. Thus, the broad goal of this proposal is to determine the biological functions of FSRP in normal and pathophysiological circumstances, as well as to elucidate the biochemical features of this protein which govern its unique biology and distribution. Transgenic and knockout mice, along with several in vitro bioassays will be utilized to identify the normal and pathophysiological actions of FSRP (Specific Aim 1). Intracellular trafficking, regulation of biosynthesis, and nuclear functions of FSRP will be examined in HeLa and human granulosa cells using pulse chase labeling, immunoprecipitation, and affinity chromatography (Specific Aim 2). The binding affinity and ligand specificity, as well as functional domains of FSRP responsible for these activities and FSRP's nuclear localization will be examined using site directed mutagenesis and domain swapping with FS (Specific Aim 3). The results of the proposed research program will define the role(s) of FSRP in normal physiology, determine the mechanism whereby FSRP overexpression disrupts folliculogenesis, and define the novel regulatory mechanisms that results in nuclear localization and activity of a protein that is also secreted.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD039777-04
Application #
6760114
Study Section
Biochemical Endocrinology Study Section (BCE)
Program Officer
Taymans, Susan
Project Start
2001-08-01
Project End
2006-07-31
Budget Start
2004-08-01
Budget End
2005-07-31
Support Year
4
Fiscal Year
2004
Total Cost
$381,366
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
073130411
City
Boston
State
MA
Country
United States
Zip Code
02199
Oldknow, Karla J; Seebacher, Jan; Goswami, Tapasree et al. (2013) Follistatin-like 3 (FSTL3) mediated silencing of transforming growth factor ýý (TGFýý) signaling is essential for testicular aging and regulating testis size. Endocrinology 154:1310-20
Sidis, Yisrael; Mukherjee, Abir; Keutmann, Henry et al. (2006) Biological activity of follistatin isoforms and follistatin-like-3 is dependent on differential cell surface binding and specificity for activin, myostatin, and bone morphogenetic proteins. Endocrinology 147:3586-97
Xia, Yin; Sidis, Yisrael; Mukherjee, Abir et al. (2005) Localization and action of Dragon (repulsive guidance molecule b), a novel bone morphogenetic protein coreceptor, throughout the reproductive axis. Endocrinology 146:3614-21
Saito, Seiichiro; Sidis, Yisrael; Mukherjee, Abir et al. (2005) Differential biosynthesis and intracellular transport of follistatin isoforms and follistatin-like-3. Endocrinology 146:5052-62
Sidis, Yisrael; Schneyer, Alan L; Keutmann, Henry T (2005) Heparin and activin-binding determinants in follistatin and FSTL3. Endocrinology 146:130-6
Schneyer, Alan (2004) Inhibins: a historical perspective. Semin Reprod Med 22:161-4
Schneyer, Alan; Schoen, Amy; Quigg, Alicia et al. (2003) Differential binding and neutralization of activins A and B by follistatin and follistatin like-3 (FSTL-3/FSRP/FLRG). Endocrinology 144:1671-4
Welt, Corrine; Sidis, Yisrael; Keutmann, Henry et al. (2002) Activins, inhibins, and follistatins: from endocrinology to signaling. A paradigm for the new millennium. Exp Biol Med (Maywood) 227:724-52
Sidis, Yisrael; Tortoriello, Drew V; Holmes, William E et al. (2002) Follistatin-related protein and follistatin differentially neutralize endogenous vs. exogenous activin. Endocrinology 143:1613-24
Tortoriello, D V; Sidis, Y; Holtzman, D A et al. (2001) Human follistatin-related protein: a structural homologue of follistatin with nuclear localization. Endocrinology 142:3426-34