This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Xie, Y.-L.
Right arrow Articles by Dufau, M. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Xie, Y.-L.
Right arrow Articles by Dufau, M. L.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, May 2009, p. 2546-2555, Vol. 29, No. 10
0270-7306/09/$08.00+0     doi:10.1128/MCB.01716-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Intramolecular Disulfide Bonds of the Prolactin Receptor Short Form Are Required for Its Inhibitory Action on the Function of the Long Form of the Receptor{triangledown}

Y.-L. Xie,1,{dagger} S. A. Hassan,2,{dagger} A. M. Qazi,1 C. H. Tsai-Morris,1 and M. L. Dufau1*

Section on Molecular Endocrinology, Endocrinology and Reproduction Research Branch, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institutes of Child Health and Human Development,1 Center for Molecular Modeling, DCB/CIT, National Institutes of Health, Bethesda, Maryland 20892-45102

Received 7 November 2008/ Returned for modification 17 December 2008/ Accepted 23 February 2009

The short form (S1b) of the prolactin receptor (PRLR) silences prolactin-induced activation of gene transcription by the PRLR long form (LF). The functional and structural contributions of two intramolecular disulfide (S-S) bonds within the extracellular subdomain 1 (D1) of S1b to its inhibitory function on the LF were investigated. Mutagenesis of the paired cysteines eliminated the inhibitory action of S1b. The expression of the mutated S1b (S1bx) on the cell surface was not affected, indicating native-like folding of the receptor. The constitutive JAK2 phosphorylation observed in S1b was not present in cells expressing S1bx, and JAK2 association was disrupted. BRET50 (BRET50 represents the relative affinity as acceptor/donor ratio required to reach half-maximal BRET [bioluminescence resonance energy transfer] values) showed decreased LF/S1bx heterodimeric-association and increased affinity in S1bx homodimerization, thus favoring LF homodimerization and prolactin-induced signaling. Computer modeling based on the PRLR crystal structure showed that minor changes in the tertiary structure of D1 upon S-S bond disruption propagated to the quaternary structure of the homodimer, affecting the dimerization interface. These changes explain the higher homodimerization affinity of S1bx and provide a structural basis for its lack of inhibitory function. The PRLR conformation as stabilized by S-S bonds is required for the inhibitory action of S1b on prolactin-induced LF-mediated function and JAK2 association.

* Corresponding author. Mailing address: Bldg. 49, Rm. 6A-36, 49 Convent Drive, MSC 4510, NIH, Bethesda, MD 20892-4510. Phone: (301) 496-2021. Fax: (301) 480-8010. E-mail: dufaum{at}mail.nih.gov

{triangledown} Published ahead of print on 9 March 2009.

{dagger} Y.-L.X. and S.A.H. contributed equally to this study.

Molecular and Cellular Biology, May 2009, p. 2546-2555, Vol. 29, No. 10
0270-7306/09/$08.00+0     doi:10.1128/MCB.01716-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»