Beryllium Fluoride and Phalloidin Restore Polymerizability of a Mutant Yeast Actin (V266G,L267G) with Severely Decreased Hydrophobicity in a Subdomain 3/4 Loop

Bing Kuang; Peter A Rubenstein

doi:10.1074/jbc.272.2.1237

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Beryllium Fluoride and Phalloidin Restore Polymerizability of a Mutant Yeast Actin (V266G,L267G) with Severely Decreased Hydrophobicity in a Subdomain 3/4 Loop

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Beryllium Fluoride and Phalloidin Restore Polymerizability of a Mutant Yeast Actin (V266G,L267G) with Severely Decreased Hydrophobicity in a Subdomain 3/4 Loop

Bing Kuang and Peter A Rubenstein

The Journal of biological chemistry, Vol.272(2), pp.1237-1247

01/10/1997

DOI: 10.1074/jbc.272.2.1237

PMID: 8995427

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Abstract

Holmes proposed that in F-actin, hydrophobic residues in a subdomain 3/4 loop interact with a hydrophobic pocket on the opposing strand resulting in helix stabilization. We have determined how a decreased hydrophobicity of this plug affects yeast actin function. Cells harboring only the V266G, V266D, V266F, L267G, L269D, or L269K actins appear normal, although V266G cells display an altered budding pattern. However, V266G,L267G (GG) double mutant cells are cold-sensitive with randomly oriented thick actin assemblies seen in rhodamine phalloidin-stained GG cells. V266D actin polymerizes slower than wild-type actin at room temperature. At 4 degrees C, not only is polymerization slowed, but there is also an effect on critical concentration. However, the polymerization defects are milder than those associated with substitution of Asp for the neighboring Leu267. Purified GG-actin does not polymerize in vitro alone or in the presence of wild-type F-actin seeds. GG-actin polymerization can be restored by larger amounts of wild-type actin, beryllium fluoride, or phalloidin at room temperature, although at 4 degrees C only phalloidin is effective. These results suggest that the diminished hydrophobicity of the plug in GG-actin leads to filament destabilization. However, the V266D actin results require a modification of the original Holmes filament model.

Details

Title: Subtitle: Beryllium Fluoride and Phalloidin Restore Polymerizability of a Mutant Yeast Actin (V266G,L267G) with Severely Decreased Hydrophobicity in a Subdomain 3/4 Loop
Creators: Bing Kuang
Peter A Rubenstein
Resource Type: Journal article
Publication Details: The Journal of biological chemistry, Vol.272(2), pp.1237-1247
DOI: 10.1074/jbc.272.2.1237
PMID: 8995427
NLM abbreviation: J Biol Chem
ISSN: 0021-9258
eISSN: 1083-351X
Language: English
Date published: 01/10/1997
Academic Unit: Stead Family Department of Pediatrics; Biochemistry and Molecular Biology; Internal Medicine
Record Identifier: 9984025288202771

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