Volume 272, Number 32, Issue of August 8, 1997 pp. 19752-19757
©1997 by The American Society for Biochemistry and Molecular Biology, Inc.

Ciliary Neurotrophic Factor Stimulates the Phosphorylation of Two Forms of STAT3 in Chick Ciliary Ganglion Neurons

(Received for publication, September 20, 1996, and in revised form, April 23, 1997)

From the Department of Biochemical Pharmacology, State University of New York, Buffalo, New York 14260

Ciliary neurotrophic factor (CNTF) is a neuropoietic cytokine that was identified, purified, and cloned based on its neurotrophic activity on cultured chick ciliary ganglion neurons. The molecular mechanisms by which CNTF elicits its effects on these neurons are unknown. We have previously identified functional receptors for CNTF on ciliary ganglion neurons and demonstrated the CNTF-specific tyrosine phosphorylation of an approximately 90-kDa protein. Here we show that CNTF induced the rapid tyrosine phosphorylation and nuclear accumulation of this protein and identify it as an avian form of the transcription factor, STAT3. Identification was confirmed by its recognition with two distinct anti-STAT3 antibodies and the lack of binding to antibodies against STAT1, -2, -4, -5, or -6. The phosphorylation was stable for up to 2 h but required the continued presence of CNTF. CNTF also induced the tyrosine phosphorylation of a similar protein in cultured chick dorsal root ganglion and retinal neurons. In addition, we identify a second, 100-kDa form of STAT3 that appears in response to CNTF. Unlike previous reports, utilizing mammalian cell lines that detected a slower migrating form of STAT3 resulting from H7-sensitive protein phosphorylation, H7 did not prevent the appearance of the 100-kDa form in ciliary neurons. Thus, the 100-kDa avian protein may represent a novel form of CNTF-inducible STAT3.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				R. K. Monroe and S. W. Halvorsen Mercury Abolishes Neurotrophic Factor-Stimulated Jak-STAT Signaling in Nerve Cells by Oxidative Stress Toxicol. Sci., November 1, 2006; 94(1): 129 - 138. [Abstract] [Full Text] [PDF]

				X. Wang and S. W. Halvorsen Reciprocal Regulation of Ciliary Neurotrophic Factor Receptors and Acetylcholine Receptors during Synaptogenesis in Embryonic Chick Atria J. Neurosci., September 15, 1998; 18(18): 7372 - 7380. [Abstract] [Full Text] [PDF]