Tropomyosin isoforms in rat neurons: the different developmental profiles and distributions of TM-4 and TMBr-3 are consistent with different functions.
Antipeptide antisera specific for TM-4 and TMBr-3, the two tropomyosin isoforms in neurons, were used to investigate the concentrations and distributions of these F-actin-binding proteins in neurons in vitro and in vivo. TM-4 and TMBr-3 tropomyosins had different developmental profiles. TM-4 was found mainly in immature stages, while the concentration of TMBr-3 increased with maturation. The two isoforms also had different subcellular distributions. TM-4 was concentrated in the growth cones of cultured neurons and, in vivo, in areas where neurites were growing. Later, when development was complete, TM-4 was restricted to postsynaptic sites in the cerebellar cortex, whereas TMBr-3 was found in the presynaptic terminals. These data suggest that the tropomyosin isoforms have different functions, through their interaction with the actin cytoskeleton. TM-4 may be involved in the motile events of neurite growth and synaptic plasticity, while TMBr-3 could play a role in stabilizing neuronal networks and synaptic functioning.
Had
L
L
Laboratoire de Neurobiologie Endocrinologique, URA 1197 CNRS, Université Montpellier II, France.
Faivre-Sarrailh
C
C
Legrand
C
C
Méry
J
J
Brugidou
J
J
Rabié
A
A
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D002531:Cerebellum / Q000737:chemistry* / Q000254:growth & development; D007106:Immune Sera; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000502:physiology; D009474:Neurons / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D013329:Structure-Activity Relationship; D013569:Synapses / Q000737:chemistry; D014335:Tropomyosin / Q000737:chemistry* / Q000502:physiology
D007106:Immune Sera; D009419:Nerve Tissue Proteins; D014335:Tropomyosin