Tubulin-G protein interactions involve microtubule polymerization domains

Journal Article · Tue Nov 12 04:00:00 EST 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00109a021· OSTI ID:5559201

Wang, Nan; Rasenick, M M ^[1]

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1. Univ. of Illinois, Chicago (United States)

It has been suggested that elements of the cytoskeleton contribute to the signal transduction process and that they do so in association with one or more members of the signal-transducing G protein family. Relatively high-affinity binding between dimeric tubulin and the {alpha} subunits of G{sub s} and G{sub i1} has also been reported. Tubulin molecules, which exist in solution as {alpha}{beta} dimers, have binding domains for microtubule-associated proteins as well as for other tubulin dimers. This study represents an attempt to ascertain whether the association between G proteins and tubulin occurs at one of these sites. Removal of the binding site for MAP2 and tau from tubulin by subtilisin proteolysis did not influence the association of tubulin with G protein, as demonstrated in overlay studies with ({sup 125}I)tubulin. However, ring structures formed from subtilisin-treated tubulin were incapable of effecting such inhibition. Stable G protein-tubulin complexes were formed, and these were separated from free tubulin by Octyl-Sepharose chromatography. Using this methodology, it was demonstrated that assembled microtubules bound G protein quite weakly compared with tubulin dimers. The {alpha} subunit of G{sub i1} and, to a lesser extent, that of G{sub o} were demonstrated to inhibit microtubule polymerization. In aggregate, these data suggest that dimeric tubulin binds to the {alpha} subunits of G protein at the sites where it binds to other tubulin dimers during microtubule polymerization. Interaction with signal-transducing G proteins, thus, might represent a role for tubulin dimers which is independent of microtubule formation.

• OSTI ID: 5559201
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:45; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AQUEOUS SOLUTIONS
BETA DECAY RADIOISOTOPES
CELL CONSTITUENTS
CYCLASES
DAYS LIVING RADIOISOTOPES
DISPERSIONS
ELECTRON CAPTURE RADIOISOTOPES
ELECTRON MICROSCOPY
ENZYMES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LYASES
MAMMALS
MEMBRANE PROTEINS
MICROSCOPY
MICROTUBULES
MIXTURES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
RADIORECEPTOR ASSAY
RATS
RECEPTORS
RODENTS
SOLUTIONS
TRACER TECHNIQUES
TRANSMISSION ELECTRON MICROSCOPY
VERTEBRATES