Spectrin-actin associations studied by electron microscopy of shadowed preparations

Journal Article · Wed Oct 01 04:00:00 EDT 1980 · Cell; (United States)

DOI:https://doi.org/10.1016/0092-8674(80)90451-1· OSTI ID:5247536

Cohen, C M ^[1]; Tyler, J M; Branton, D

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1. Saint Elizabeth's Hospital, Boston, MA

By shadowing specimens dried onto mica sheets we have obtained clear images of actin crosslinked by spectrin, an actin-binding protein found in erythrocytes. We conclude that spectrin dimers possess a single binding site for F actin. Tetramers formed by head-to-head association of two dimers possess two actin binding sites, one at each tail. Polymerizing G actin in the presence of spectrin tetramers or mixing preformed F actin with spectrin tetramer plus band 4.1 results in an extensively crosslinked network of actin filaments. When G actin is polymerized in the presence of spectrin at spectrin:actin mole ratios close to that present on the erythrocyte membrane, large amorphous protein networks are formed. These networks are clusters of spectrin around 25 nm diameter structures which may be actin protofilaments. These networks are similar to the cytoskeletal network seen after erythrocyte membranes are extracted with detergent, and may represent the first in vitro assembly of a cytoskeletal complex resembling that of the native cell both biochemically and structurally.

• OSTI ID: 5247536
• Journal Information: Cell; (United States), Journal Name: Cell; (United States) Vol. 21; ISSN CELLB
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ACTIN
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CROSS-LINKING
DIMERS
ELECTRON MICROSCOPY
ERYTHROCYTES
KINETICS
MATERIALS
MEMBRANES
MICA
MICROSCOPY
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
POLYMERIZATION
PROTEINS
REACTION KINETICS