A tissue-specific exon of myosin Va is responsible for selective cargo binding in melanocytes.
Class V myosins are molecular motors used for intracellular transportation and organelle tethering. The mouse Myosin Va (MyoVa) is encoded by the dilute locus, which is alternatively spliced to generate several tissue specific isoforms. The tail of MyoVa is the putative cargo-binding domain. To determine the functions of different isoforms of MyoVa and the minimal cargo-binding region, we tagged various isoforms and different portions of the mouse MyoVa tail with a green fluorescent protein and examined their intracellular localizations in the mouse melan-a cells. We found that the amino acid sequence encoded by an alternatively spliced exon, exon F, is necessary for the selective binding of MyoVa to melanosome. The MyoVa isoforms lacking this amino acid sequence are not targeted to the melanosomes, but localized to the perinuclear region instead. These findings suggested that MyoVa is able to bind to more than one types of cargos, with the selectivities determined by alternative spliced sequences.
Au
Josephine Sui-Yan
JS
Department of Biochemistry, Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China.
Huang
Jian-Dong
JD
D017398:Alternative Splicing; D000818:Animals; D001665:Binding Sites; D001692:Biological Transport / Q000502:physiology*; D002478:Cells, Cultured; D005091:Exons / Q000235:genetics*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008544:Melanocytes / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D020409:Molecular Motor Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D018995:Myosin Heavy Chains / Q000235:genetics* / Q000378:metabolism; D024701:Myosin Type V / Q000235:genetics* / Q000378:metabolism; D016716:PC12 Cells; D010641:Phenotype; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D008164:Luminescent Proteins; D020409:Molecular Motor Proteins; C513082:Myo5a protein, mouse; C513081:Myo5a protein, rat; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D024701:Myosin Type V; D018995:Myosin Heavy Chains