The general objective of the proposed studies is to continue the molecular and functional characterization of myosin-VI (Myo6). Myo6 is unique among known members of the myosin superfamily of actin based molecular motors in that it moves in the opposite direction along the actin filament, toward the pointed/minus end. Past studies have implicated several potential functions for Myo6 including clathrin mediated endocytosis, Golgi traffic and cellular motility. The health relevance of the proposed studies has been well established as this myosin is a target for mutations that lead to inherited deafness and cardiac myopathies. It also has been shown to be a key contributor to the invasiveness of ovarian tumor cells. The goals of this project are three fold. The first will be to conduct an extensive characterization of the motor properties of native tissue purified Myo6. Our studies indicate that native Myo6 has properties significantly different from in-vitro expressed Myo6. Proposed studies will examine the motility of native Myo6 with respect to duty ratio and regulation by calcium, phosphorylation and load. A major focus will be the molecular basis for the conversion of Myo6 from a minus- to a plus- end directed motor. The second goal will be the phenotypic characterization of the cellular and physiologic defects in the proximal tubule epithelial (PTE) cells of the kidney in the Myo6 mutant mouse?Snell's waltzer. Like humans with Myo6 mutations, these mice are deaf due to degeneration of the neurosensory epithleum of the inner ear. Although this is the only overt dysfunction in these mice, our preliminary findings indicate that there are also serious cellular deficiencies in a number of tissues that express Myo6 including the renal proximal tubule. Studies will include assessment of defects in PTE architecture, endocytosis of glomerular filtrate, and responses to renal injuries including ischemia and chemically induced diabetes. The third goal will focus on the in vivo dynamics of fluorescently tagged Myo6 expressed in a PTE cell line and how cellular functions including endocytosis, wound healing and organization of the actin cytoskeleton are affected by targeted disruption of Myo6 function.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
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Cell Structure and Function (CSF)
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Deatherage, James F
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Yale University
Schools of Arts and Sciences
New Haven
United States
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Hegan, Peter S; Giral, Hector; Levi, Moshe et al. (2012) Myosin VI is required for maintenance of brush border structure, composition, and membrane trafficking functions in the intestinal epithelial cell. Cytoskeleton (Hoboken) 69:235-51
Chandhoke, Surjit K; Mooseker, Mark S (2012) A role for myosin IXb, a motor-RhoGAP chimera, in epithelial wound healing and tight junction regulation. Mol Biol Cell 23:2468-80
Ramamurthy, Bhagavathi; Cao, Wenxiang; De la Cruz, Enrique M et al. (2012) Plus-end directed myosins accelerate actin filament sliding by single-headed myosin VI. Cytoskeleton (Hoboken) 69:59-69
Gotoh, Nanami; Yan, Qingshang; Du, Zhaopeng et al. (2010) Altered renal proximal tubular endocytosis and histology in mice lacking myosin-VI. Cytoskeleton (Hoboken) 67:178-92
Collaco, Anne; Jakab, Robert; Hegan, Peter et al. (2010) Alpha-AP-2 directs myosin VI-dependent endocytosis of cystic fibrosis transmembrane conductance regulator chloride channels in the intestine. J Biol Chem 285:17177-87
Krendel, Mira; Kim, Sangwon V; Willinger, Tim et al. (2009) Disruption of Myosin 1e promotes podocyte injury. J Am Soc Nephrol 20:86-94
Chang, Wakam; Zaarour, Rania F; Reck-Peterson, Samara et al. (2008) Myo2p, a class V myosin in budding yeast, associates with a large ribonucleic acid-protein complex that contains mRNAs and subunits of the RNA-processing body. RNA 14:491-502
Krendel, Mira; Osterweil, Emily K; Mooseker, Mark S (2007) Myosin 1E interacts with synaptojanin-1 and dynamin and is involved in endocytosis. FEBS Lett 581:644-50
O'Connell, Christopher B; Tyska, Matthew J; Mooseker, Mark S (2007) Myosin at work: motor adaptations for a variety of cellular functions. Biochim Biophys Acta 1773:615-30
Holt, Jeffrey P; Bottomly, Kim; Mooseker, Mark S (2007) Assessment of myosin II, Va, VI and VIIa loss of function on endocytosis and endocytic vesicle motility in bone marrow-derived dendritic cells. Cell Motil Cytoskeleton 64:756-66

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