The G Protein

The G Protein-Ras

This web page was produced as an assignment for an undergraduate course at Davidson College.

Cells interact with the extracellular environment by cell-surface receptors which recognize and bind with antigen. Specifically, the T and B lymphocytes that have bound their particular antigen produce a series of intricate intracellular signals that respond to the stimulus. This process of transmitting, and often amplifying a signal, through the cell is known as signal transduction (Campbell, 1996). One major pathway of signal transduction occurs by way of Ras. Ras is a small protein that is activated by GTP and is thus in the class of G proteins (Janeway et al., 1999). The Ras family consists numerous different Ras proteins, however of most importance are the human H-, K-, and N-Ras proteins (Boguski et al., 1993)

TABLE OF CONTENTS

Structure and Pathways

Ras Activation, Mutation, and Research

Figure 1- The back bone of the small G protein Ras. Typical Ras molecules contain approximately 190 residues (Boguski et al., 1993). This image is used with permission from Dr. Raymond Mosteller at the University of Southern California Keck School of Medicine (http://www-hsc.usc.edu/~rmostell/).

OVERVIEW

The small G protein Ras regulates many aspects of cell growth and differentiation and for this reason has been under intense study in the past decade. In fact recent discoveries link the Ras superfamily to tumorigenicicy (Boguski et al., 1993). Ras is found in two states: the active state when GTP is bound and the inactive state, when GDP is bound. Tumorigenicity is prevellant when mutations allow Ras to remain activated state, thus relaying a signal for cell growth (Bourne et al., 1990).

This web site was created for an Immunology class. Please direct correspondence to jodickens@davidson.edu.

Last Updated March 3, 1999

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