scholarly journals Unconventional Myosin-Va

2020 ◽  
Author(s):  
Keyword(s):  
Unconventional Myosin ◽  
Myosin Va

Molecular Genetic Dissection of Mouse Unconventional Myosin-VA: Tail Region Mutations

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1963-1972 ◽  
Author(s):  
Jian-Dong Huang ◽  
Valerie Mermall ◽  
Marjorie C Strobel ◽  
Liane B Russell ◽  
Mark S Mooseker ◽  
...  
Keyword(s):  
Coat Color ◽  
Molecular Genetic ◽  
Genetic Dissection ◽  
Rt Pcr ◽  
Tail Region ◽  
Unconventional Myosin ◽  
Myosin Va ◽  
Cell Type Specific ◽  
Extensive Collection ◽  
Tail Function

AbstractWe used an RT-PCR-based sequencing approach to identify the mutations responsible for 17 viable dilute alleles, a mouse-coat-color locus encoding unconventional myosin-VA. Ten of the mutations mapped to the MyoVA tail and are reported here. These mutations represent the first extensive collection of tail mutations reported for any unconventional mammalian myosin. They identify sequences important for tail function and identify domains potentially involved in cargo binding and/or proper folding of the MyoVA tail. Our results also provide support for the notion that different myosin tail isoforms produced by alternative splicing encode important cell-type-specific functions.

Molecular Genetic Dissection of Mouse Unconventional Myosin-VA: Head Region Mutations

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1951-1961
Author(s):  
Jian-Dong Huang ◽  
M Jamie T V Cope ◽  
Valerie Mermall ◽  
Marjorie C Strobel ◽  
John Kendrick-Jones ◽  
...  
Keyword(s):  
Coat Color ◽  
Smooth Endoplasmic Reticulum ◽  
Molecular Genetic ◽  
Motor Domain ◽  
Null Alleles ◽  
Genetic Dissection ◽  
Head Region ◽  
Unconventional Myosin ◽  
Ultrastructural Studies ◽  
Myosin Va

Abstract The mouse dilute (d) locus encodes unconventional myosin-VA (MyoVA). Mice carrying null alleles of dilute have a lightened coat color and die from a neurological disorder resembling ataxia and opisthotonus within three weeks of birth. Immunological and ultrastructural studies suggest that MyoVA is involved in the transport of melanosomes in melanocytes and smooth endoplasmic reticulum in cerebellar Purkinje cells. In studies described here, we have used an RT-PCR-based sequencing approach to identify the mutations responsible for 17 viable dilute alleles that vary in their effects on coat color and the nervous system. Seven of these mutations mapped to the MyoVA motor domain and are reported here. Crystallographic modeling and mutant expression studies were used to predict how these mutations might affect motor domain function and to attempt to correlate these effects with the mutant phenotype.

scholarly journals A Coiled-Coil Domain of Melanophilin Is Essential for Myosin Va Recruitment and Melanosome Transport in Melanocytes

2006 ◽  
Vol 17 (11) ◽  
pp. 4720-4735 ◽  
Author(s):  
Alistair N. Hume ◽  
Abul K. Tarafder ◽  
José S. Ramalho ◽  
Elena V. Sviderskaya ◽  
Miguel C. Seabra
Keyword(s):  
Coiled Coil ◽  
Binding Domain ◽  
Actin Binding ◽  
Binding Studies ◽  
Null Cell ◽  
Coiled Coil Region ◽  
Actin Binding Domain ◽  
Transport Assay ◽  
Myosin Va

Melanophilin (Mlph) regulates retention of melanosomes at the peripheral actin cytoskeleton of melanocytes, a process essential for normal mammalian pigmentation. Mlph is proposed to be a modular protein binding the melanosome-associated protein Rab27a, Myosin Va (MyoVa), actin, and microtubule end-binding protein (EB1), via distinct N-terminal Rab27a-binding domain (R27BD), medial MyoVa-binding domain (MBD), and C-terminal actin-binding domain (ABD), respectively. We developed a novel melanosome transport assay using a Mlph-null cell line to study formation of the active Rab27a:Mlph:MyoVa complex. Recruitment of MyoVa to melanosomes correlated with rescue of melanosome transport and required intact R27BD together with MBD exon F–binding region (EFBD) and unexpectedly a potential coiled-coil forming sequence within ABD. In vitro binding studies indicate that the coiled-coil region enhances binding of MyoVa by Mlph MBD. Other regions of Mlph reported to interact with MyoVa globular tail, actin, or EB1 are not essential for melanosome transport rescue. The strict correlation between melanosomal MyoVa recruitment and rescue of melanosome distribution suggests that stable interaction with Mlph and MyoVa activation are nondissociable events. Our results highlight the importance of the coiled-coil region together with R27BD and EFBD regions of Mlph in the formation of the active melanosomal Rab27a-Mlph-MyoVa complex.

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