Ian C. Brett

3rd Year PhD Student

Department: Biochemistry & Cell Biology

Graduate Program: Biochemistry & Structural Biology

Advisor: Steven Smith

Abstract:

Title: The Role of the Transmembrane and Juxtamembrane Regions of Cytokine Receptors in Signal Transduction

Cytokine receptors such as EpoR and TpoR are single pass transmembrane (TM) proteins that as monomers consist of an extracellular (EC) domain, a TM alpha helix, and an intracellular (IC) domain. Upon ligand binding, changes in EC domain position/structure are transmitted through the TM domain to the IC domain, allowing Jak2 activation and phosphorylation of tyrosine residues in the cytoplasmic domain of the receptor as well as Jak2 itself. This causes a cascade of signal transduction resulting in the production of RBCs or platelets. Structural analysis of these proteins has typically focused solely on the EC domain where ligand binds because these hydrophilic domains are easily crystallized. Mechanisms of activation have been proposed based on dimerization mediated through the EC domain. However, research from our lab and others suggests that dimerization occurs via TM domain association, which would change the constraints used to define the method of receptor activation. This evidence suggests that the best way to elucidate the initiation of the intracellular signaling cascade is to solve the high-resolution solution NMR structure of the entire protein. By using a combination of analytical ultracentrifugation and NMR to study the oligomerization status and structure of a complex combination of expressed protein constructs and isotopically labeled synthesized peptides, we hope to do just that. These insights will aid us in proposing a general model for the activation of cytokine receptors and could facilitate the development of new pharmacotherapies for the treatment of erythropoietic diseases.

Publications:
(MSTP-supported publications indicated with an *)

Johansson BE, Brett IC. (2007). Changing perspective on immunization against influenza. Vaccine. 25(16):3062-5.

Brett, I.C., and B.E. Johansson. (2006). Influenza B virus hemagglutinin and neuraminidase induce immunity similar to Influenza A and protect mice from infectious challenge. Submitted to Virology.

Brett IC, Johansson BE. (2006). Variation of divalent cation requirements of influenza A virus N1 neuraminidases. J Biochem. 136:439-447.

Johansson BE, Brett IC. (2006). An inactivated subvirion influenza A (H5N1) vaccine. NEJM. 354(25):2724-5. (Letter to the editor)

Brett IC, Johansson BE. (2005). Immunization against Influenza A virus: Comparison of conventional inactivated, live-attenuated, and recombinant baculovirus produced purified hemagglutinin and neuraminidase vaccines in a murine model system. Virology. 339(2):273-80.

Noy A, Yahalom J, Zaretsky L, Brett I, Zelenetz AD. (2005). Gastric mucosa-associated lymphoid tissue detected by clonotypic polymerase chain reaction despite continuous pathologic remission induced by involved-field radiotherapy. J Clin Oncol. 23(16):3768-72.

Kilbourne ED, Pokorny BA, Johansson B, Brett I, Milev Y, Matthews JT. (2004). Protection of mice with recombinant influenza virus neuraminidase. J Infect Dis. 189(3):459-61.

Brown ST, Brett I, Almenoff PL, Lesser M, Terrin M, Teirstein AS. (2003). Recovery of cell wall deficient organisms from blood does not distinguish between subjects with sarcoidosis and controls. Chest. 123(2):413-7.

Johansson, BE and Brett, IC. (2003). Variation in divalent cation requirements of influenza A virus N2 neuraminidases. J Biochem. 134(2):345-352.

Brett, I., J. Werber, and E.D. Kilbourne. (2002). Rapid confirmation by RFLP of transfer to vaccine candidate reassortment viruses of the principal 'high yield' gene of influenza A viruses. J Virol Methods. 100:133-40.

Kilbourne ED, Smith C, Brett I, Pokorny BA, Johansson B, Cox N. (2002). The total influenza vaccine failure of 1947 revisited: Major intrasubtypic antigenic change can explain failure of vaccine in a post-World War II epidemic. Proc Nat Acad Sci. 99(16):10748-10752.