Immunohistochemical localization of myosin va in the adult rat brain

Abstract

Abstract-Brain myosin Va (MVa) is a molecular motor associated with plastic changes during development. MVa has previously been detected in the cell body and in dendrites of neuronal cells in culture, in cells of the guinea-pig cochlea, as well as in cerebellar cells. Adult Wistar rats (n‫,)41؍‬ 250 -300 g, were perfused with standard methods for immunohistochemistry, using a polyclonal, affinity-purified rabbit antibody against MVa tail domain. Anti-MVa antibody specifically stained neuronal nuclei from forebrain to cerebellar regions, and more intensely sensory nuclei. Differences in MVa immunoreactivity were detected between brain nuclei, ranging from very intense to weak staining. The analysis of MVa and glial fibrillary acidic protein staining in adjacent brain sections demonstrated a clear-cut neuronal labeling rather than an astroglial staining. The studies presented here represent a comprehensive map of MVa regional distribution in the CNS of the adult rat and may contribute to the basic understanding of its role in brain function and plasticity, particularly in relationship to phenomena that involve molecular motors, such as neurite outgrowth, organelle transport and neurotransmitter-vesicle cycling. It is important to highlight that this is a pioneer immunohistochemical study on the distribution of MVa on the whole brain of adult rats, a first step toward the understanding of its function in the CNS.

Myosin-Va Regulates Exocytosis through the Submicromolar Ca2+-dependent Binding of Syntaxin-1A

“…This latter report used cultured neurons derived from 1-d-old mice, whereas Schnell and Nicoll (2001) used tissue slices obtained from 12-to 19-d-old mice, suggesting that the differences may be due to the age of the mice used in the studies. Furthermore, according to a recent detailed immunohistochemical study the brain (Tilelli et al, 2003), the hippocampus does not express much myosin-Va, and most of the myosin-Va immunoreactivity is associated with the neuronal cell bodies rather than the neuropila, which are enriched with synaptic terminals. Thus, differences in the levels of myosin-Va in hippocampal synapses mutant between wild-type and the dilute lethal may be subtle.…”

“…Among the three isoforms of myosin-V in higher vertebrates, myosin-Va is the most abundant, and it is highly enriched in the brain (Espreafico et al, 1992), particularly in the neurons (Tilelli et al, 2003). Several lines of evidence indicate that synaptic vesicles, which undergo the Ca 2ϩ -regulated exocytosis, are one of the most important cargoes for myosin-Va (Prekeris and Terrian, 1997;Bridgman, 1999;Tilelli et al, 2003).…”

“…Several lines of evidence indicate that synaptic vesicles, which undergo the Ca 2ϩ -regulated exocytosis, are one of the most important cargoes for myosin-Va (Prekeris and Terrian, 1997;Bridgman, 1999;Tilelli et al, 2003). In addition, Myo2p, a yeast homologue of myosin-Va, directs intracellular transport during secretion and budding through interactions with other proteins (Matsui, 2003).…”

“…In addition, the globular tail of myosin-V interacts with membrane-bound vesicles. In these ways, myosin-V plays a central role in intracellular polarized transport (Reck-Peterson et al, 2000;Matsui, 2003;Vale, 2003).Among the three isoforms of myosin-V in higher vertebrates, myosin-Va is the most abundant, and it is highly enriched in the brain (Espreafico et al, 1992), particularly in the neurons (Tilelli et al, 2003). Several lines of evidence indicate that synaptic vesicles, which undergo the Ca 2ϩ -regulated exocytosis, are one of the most important cargoes for myosin-Va (Prekeris and Terrian, 1997;Bridgman, 1999;Tilelli et al, 2003).…”

Human Myosin Vc Is a Low Duty Ratio Nonprocessive Motor

“…Class V myosins have been widely found in species from lower organisms, such as yeast, Caenorhabditis elegans, and Drosophila, to vertebrates. In vertebrates, there are three distinct subclasses of myosin V. Among them, most of the research has focused on myosin Va, which plays a critical role in membrane trafficking, including melanosome transport (1,2) and endoplasmic reticulum transport (3)(4)(5)(6). In contrast to myosin Va expressed mainly in brain and melanocytes, myosin Vb and Vc are widely expressed in a variety of tissues, although the relative expression level is distinct from each other.…”