Functional and structural studies on stress-induced protein kinase pathways / Zheng Tu.

Format:

Book

Manuscript

Microformat

Thesis/Dissertation

Author/Creator:

Du, Zheng.

Contributor:

Lee, Frank S., advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Penn dissertations--Cell and molecular biology.

Cell and molecular biology--Penn dissertations.

Cell and Molecular Biology.

Academic Dissertations as Topic.

Medical Subjects:

Cell and Molecular Biology.

Academic Dissertations as Topic.

Local Subjects:

Penn dissertations--Cell and molecular biology.

Cell and molecular biology--Penn dissertations.

Physical Description:

xiv, 167 pages : illustrations ; 29 cm

Production:

2003.

Summary:

In response to numerous stress signals, the NF-kappaB and JNK pathways are activated and as a result, the expression of many genes altered. Understanding the mechanisms by which these stress-induced signaling pathways are regulated is an important step toward identifying novel drug targets and therapies for many human diseases, including inflammatory diseases and cancer. Vascular cell adhesion molecule-1 (VCAM1) is a stress-induced protein which plays critical roles in local immune responses, as it recruits lymphocytes and monocytes expressing alpha4beta1 or alpha4beta7 integrins to sites of inflammation in response to stimuli such as TNF-alpha. VCAM1 is inducibly expressed in renal proximal tubular epithelial cells (RPTEC), which is relevant to diseases such as acute transplant rejection. However, the mechanisms behind this have yet to be elucidated. Using reporter gene assays and dominant negative constructs, we find that the IKK-IkappaB-NF-kappaB pathway is essential for TNF-alpha-induced VCAM1 transcription in RPTEC.

IKK, as well as the MAP2Ks that activate JNK, can be activated by MAP3Ks. To understand the molecular determinants by which one MAP3K, MEKK1, can activate both a MAP2K (MKK4) of the JNK pathway and IKK of NF-kappaB pathway, we employed alanine scanning mutagenesis. We find that mutation of certain residues in both subdomain VIII and subdomain X of MEKK1 can abolish the activation of MKK4 and IKK, and consequently AP1 and NF-kappaB reporter genes. Most interestingly, we find that mutations of other residues, namely Ile-1394 and Leu-1402 of subdomain VIII, have differential effects on the capacity of MEKK1 to activate JNK and NF-kappaB pathways. Consistent with a critical role of subdomain VIII in recognition of substrates, we find that MKK4 protects MEKK1 from proteolysis at an engineered cleavage site in subdomain VIII.

Notes:

Adviser: Frank S. Lee.

Thesis (Ph.D. in Cell and Molecular Biology) -- University of Pennsylvania, 2003.

Includes bibliographical references.

Local Notes:

University Microfilms order no.: 3095954.

OCLC:

244973667