Axonal transport of actin and actin-binding proteins in the rat sciatic nerve.
Actin is one of the major cytoskeletal proteins carried in slow axonal transport. Since more than 50% of actin in the axon was recovered in the high-speed supernatant, we looked for G-actin-binding proteins in slow axonal transport. Two weeks after injection of L-[35S]methionine into the rat spinal cord (L3-L5), labeled proteins in the sciatic nerve were extracted and those with potential abilities to interact with G-actin were detected by two independent methods: (A) DNAase I affinity chromatography and (B) blot overlay with biotinylated actin. By method (A), a 68 kDa Ca(2+)-dependent binding protein and a 45 kDa Ca(2+)-independent binding protein were detected. The 68 kDa protein was also a major protein binding to actin in method (B). The 68 kDa protein was identified with the Ca(2+)-dependent phospholipid binding protein annexin VI by two-dimensional electrophoresis and Western blotting. As annexin VI is a component of slow axonal transport, it does not seem to be bound to membranous organelles in the axon. Our results suggest that annexin VI may play a role in the control of actin assembly and membrane-microfilament interaction.
Tanaka
K
K
Department of Molecular and Cellular Neurobiology, Gunma University School of Medicine, Japan.
Tashiro
T
T
Sekimoto
S
S
Komiya
Y
Y
D000199:Actins / Q000378:metabolism*; D000818:Animals; D001370:Axonal Transport; D002118:Calcium / Q000494:pharmacology; D002846:Chromatography, Affinity; D003850:Deoxyribonuclease I; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D015151:Immunoblotting; D008297:Male; D008715:Methionine / Q000378:metabolism; D008840:Microfilament Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology; D013462:Sulfur Radioisotopes
D000199:Actins; D008840:Microfilament Proteins; D013462:Sulfur Radioisotopes; D008715:Methionine; D003850:Deoxyribonuclease I; D002118:Calcium