Inhibition of DNA synthesis in living cells by microinjection of Gi2 antibodies

• Published in: The Journal of biological chemistry 1992-01, Vol.267 (2), p.691-694
• Main Authors: LaMorte, V J, Goldsmith, P K, Spiegel, A M, Meinkoth, J L, Feramisco, J R
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Animals; Biological and medical sciences; Blood; Cell cycle, cell proliferation; Cell physiology; DNA - antagonists & inhibitors; DNA - biosynthesis; Fundamental and applied biological sciences. Psychology; GTP-Binding Proteins - immunology; GTP-Binding Proteins - metabolism; Mice; Mice, Inbred BALB C; Microinjections; Microscopy, Fluorescence; Molecular and cellular biology; Platelet-Derived Growth Factor - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)48337-8

Heterotrimeric guanine nucleotide binding proteins function in the coupling of a diverse span of cell surface receptors to a variety of intracellular signaling pathways, some of which stimulate cellular proliferation. With the recent discovery that mutated forms of G proteins are present in specific tumors, there has been an increased interest in the determination of the role of specific subtypes of G proteins in the regulation of cellular growth. We have attempted to determine which subtypes of G proteins are directly involved in serum-stimulated DNA synthesis through microinjection of inhibitory antibodies into living cells. Inhibitory rabbit polyclonal antibodies directed against specific Gi alpha subunits were introduced into living Balb/c 3T3 fibroblasts by microinjection, and the effect upon serum-stimulated DNA synthesis was examined. Results of these experiments indicate that Gi2 plays a direct role in serum-stimulated DNA synthesis in living cells and suggest that G proteins may function in a variety of mitogenic signaling pathways initiated by serum growth factors.