NFAT Signaling in Vertebrate Development
From Greaf et al Cell 2003 with modification
Intracellular Signaling in the Development of the Immune and Nervous Systems.
How do cells percieve and respond to their environment? This question inspired the origin of our lab and lead to the elucidation of the NFAT signaling pathway that plays essential roles in vertebrate organogenesis and development. In this pathway, Calcium trigers the activation of calcineuirn and the dephosphorylation and nuclear entry of the different cytoplasmic subunits (NFATc proteins). In the nucleus these assemble with NFATn proteins on DNA target sites and activate or inactivate downstream genes. A wide variety of calcium souces will activate this pathway including tyrosine kinase receptor, non-receptor tyrosine kinases, L-type Calcium channels, NMDA receptors, gap junctions and non-canonical Wnt signaling. More recently we have found that, NFAT signaling can be activated by preventing export of NFATc proteins by activation of PI3 kinase and subsequent inhibition of GSK3 in the nucleus. Present studies indicate that there are likely to be many as yet undefined modulators of this pathway. For example the DSCR1 or MCIP gene implicated in Down's Syndrome is likely to be a modulatory. One of our goals is to understand the full range of biochemical modulators of the core signaling pathway.
Signaling in Neural Development. The recent discovery that NFAT signaling is essential to control the rate of axonal outgrowth in response to guidance signals (Cell 2003) has given rise to many interesting questions about the general biochemical functions of this pathway and how it is molded to the needs of the developing nervous system (see figure above). We would like to know if NFATc proteins are involved in retrograde signaling from the growth cone to the nucleus as indicated by the phenotypes of the deletions of the C3 and C4 genes. If so does retrograde signaling require movement of C3 and C4 along the axon or some other as yet undefined process. Does NFAT signaling induce the growth cone to stop when it encounters its target? What are the roles of NFAT signaling in the subsequent assembly of the synapse? We would also like to know if NFAT signaling is sufficient for axonal outgrowth and weather it has a role in regeneration of axons after injury. The later studies are being explored in collaboration with the Tessier Lavigne Laboratory, which recently moved to Genentech.
We have defined target genes for calcineurin, and C3/C4 in neurons and find that they are very similar indicating that calcineurin functions primarly by controlling NFATc proteins. We are are seeking to understand how these target genes control the rate of axonal extension in response to signals by neurotrophins, netrins and other guidance molecules. In lymphocytes we found that effective NFAT signaling requires not only Calcium, but other pathways as well, such as PKC or the Map kinase pathway (Science 1989, Nature 1991, Cell 2002) and we would like to know what these cooperating pathways are in neurons..... Next page
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NFAT Nomenclature- Recently the Genome Nomenclature Committee at HUGO called for a vote on the nomenclature and the following designation was approved:
First Description: Science. 1988;241,:202-5; :Mol Cell Biol. 1988:1715-24; Mol Cell Biol. 1986 9:3042-9 Signal Integration by NFAT transcription complexes Science. 1989;243:355-61 Cyclosporin Sensitivity Science. 1989;246:1617-20 Nuclear Translocation of cytoplasmic subunits (NFATc) Nature. 1991;352:803-7 Calcineurin requirement for NFATc translocation Nature. 1992 Jun 25;357(6380):695-7. Cloning of Cytoplasmic subunits
Identification of the SP-repeat motif Structure of the DNA binding domains NFATc1: Wolfe SA et al Nature1997 Jan 9;385(6612):172-6 NFATc1: Zhou P et al Cell. 1998 Mar 6;92(5):687-96 NFATc2 Chen et al Nature. 1998 Mar 5;392(6671):42-8 NFAT Signaling in the Development and Function of the Nervous System Graef, Wang et al Cell. 2003 May 30;113(5):657-702003 Zeng H et al Cell. 2001 Nov 30;107(5):617-29. Mansuy IM, et al Cell. 1998 Jan 9;92(1):39-49. Graef et al . Nature 1999 Oct 14;401(6754):703-8 NFAT Signaling in the Development and Function of the Cardiovascular System Molkentin JD et al Cell. 1998 Apr 17;93(2):215-28 Sussman et al Science. 1998 Sep 11;281(5383):1690-3 Graef et al Cell. 2001 Jun 29;105(7):863-75 NFAT Signaling in the Development and Function of the Immue System Macian F, et al Cell. 2002 Jun 14;109(6):719-31 Rengarajan J, Tang B, and LH Glimcher Nat Immunol. 2002 Jan;3(1):48-54 Peng SL et al Immunity. 2001 Jan;14(1):13-20 Xanthoudakis S, et al Science. 1996 May 10;272(5263):892-5. NFATc antibodies Caution- NFAT complexes are not present in conventional nuclear extracts- See our Protocols for the preparation of extracts. NFATc1 monoclonal- Nature. 1994;369:497-502- J. Immunology 1997 Our 7A6 monoclonal antibody western blots, is good for IP and quantiatively supershifts NFATc1-based complexes. It is sold by BD Pharmagene, Santa Cruz, ABI, Serotec and other companies. It is also available through the Developmental Studies Hybridoma Bank. NFATc2 monoclonal-Nature. 1994;369:497-502- J. Immunology 1997 We isolated three useful NFATc2 antibodies: G1D10 and G1G9, which give quantiative supershifts of both murine and human NFATc2-based complexes, but do not Western blot. In contrast clone 4G6-G5 Western blots well, but does not supershift and is not very useful for immunofluorescence. and 4G5D, they are good for western blots, are good for IP and supershift experiments. Theu are sold by BD Pharmagene, Santa Cruz, ABI, Serotec and other companies. NFATc3 monoclonal- Not available NFATc3 polyclonal. J Biol Chem. 1995;270:19898-907 Sold by BD Pharmagene, Santa Cruz, ABI and other companies. NFATc4 polyclonal- Limited quantities available. Requires purification to be effective. WebSites on NFAT Signaling |
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Crabtree GR, Olson EN. Cell. 2002 Apr;109 Suppl:S67-79 Olson EN, Williams RS.Cell. 2000 Jun 23;101(7):689-92 Graef and Crabtree Curr Opin Genet Dev. 2001 Oct;11(5):505-12 Crabtree GR.Cell. 1999 Mar 5;96(5):611-4 Rao A, Luo C, Hogan PG. Annu Rev Immunol. 1997;15:707-47 Crabtree and Clipstone Annu Rev Biochem. 1994;63:1045-83. Crabtree GR Science. 1989 Jan 20;243(4889):355-61.
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