Mutations Probe Structure and Function of G-protein α Chains

  1. H.R. Bourne,
  2. S.B. Masters,
  3. R.T. Miller,
  4. K.A. Sullivan, and
  5. W. Heideman
  1. Departments of Pharmacology and Medicine and the Cardiovascular Research Institute, University of California, San Francisco, California 94143-0450

This extract was created in the absence of an abstract.

Excerpt

Recent investigations have identified new members of the G-protein family and have established similarities between G proteins and other GTP-binding proteins (for review, see Stryer and Bourne 1986; Gilman 1987). All signaling pathways mediated by G proteins are driven by a single kind of molecular machine, which is conserved within and beyond the G-protein family. In the G proteins, this GTP-dependent machine transduces chemical signals, detected by receptors for sensory or hormonal stimuli outside the cell, into regulation of effector proteins that control accumulation of intracellular second messengers.

This paper summarizes what we know of the structure and function of a key element of the signaling machinery, the G-protein α polypeptide chain. We begin with a brief description of key functions of G-protein α chains and features of a structural model of a composite α chain, αavg (Masters et al, 1986). We then describe phenotypes produced by mutations in the...

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