Abstract
Previous studies proposed that myosin-Va regulates apoptosis by sequestering pro-apoptotic Bmf to the actin cytoskeleton through dynein light chain-2 (DLC2). Adhesion loss or other cytoskeletal perturbations would unleash Bmf, allowing it to bind and inhibit pro-survival Bcl2 proteins. Here, we demonstrated that overexpression of a myosin-Va medial tail fragment (MVaf) harboring the binding site for DLC2 dramatically decreased melanoma cell viability. Morphological and molecular changes, including surface blebbing, mitochondrial outer membrane permeabilization, cytochrome-c and Smac release, as well as caspase-9/-3 activation and DNA fragmentation indicated that melanoma cells died of apoptosis. Immobilized MVaf interacted directly with DLCs, but complexed MVaf/DLCs did not interact with Bmf. Overexpression of DLC2 attenuated MVaf-induced apoptosis. Thus, we suggest that, MVaf induces apoptosis by sequestering DLC2 and DLC1, thereby unleashing the pair of sensitizer and activator BH3-only proteins Bmf and Bim. Murine embryonic fibroblasts (MEFs) lacking Bim and Bmf or Bax and Bak were less sensitive to apoptosis caused by MVaf expression than wild-type MEFs, strengthening the putative role of the intrinsic apoptotic pathway in this response. Finally, MVaf expression attenuated B16-F10 solid tumor growth in mice, suggesting that this peptide may be useful as an apoptosis-inducing tool for basic and translational studies.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Adaptor Proteins, Signal Transducing / genetics
-
Adaptor Proteins, Signal Transducing / metabolism
-
Animals
-
Apoptosis / drug effects
-
Apoptosis Regulatory Proteins / deficiency
-
Apoptosis Regulatory Proteins / genetics
-
Bcl-2-Like Protein 11
-
Cell Line, Tumor
-
Cytoplasmic Dyneins / genetics*
-
Cytoplasmic Dyneins / metabolism
-
DNA Fragmentation / drug effects
-
Fibroblasts / metabolism
-
Fibroblasts / pathology
-
Gene Expression Regulation, Neoplastic / drug effects*
-
Humans
-
Melanoma / genetics*
-
Melanoma / metabolism
-
Melanoma / pathology
-
Membrane Proteins / deficiency
-
Membrane Proteins / genetics
-
Mice
-
Mice, Knockout
-
Myosin Heavy Chains / genetics*
-
Myosin Heavy Chains / metabolism
-
Myosin Type V / genetics*
-
Myosin Type V / metabolism
-
Neoplasm Transplantation
-
Peptide Fragments / genetics*
-
Peptide Fragments / metabolism
-
Peptide Fragments / pharmacology
-
Protein Binding
-
Proto-Oncogene Proteins / deficiency
-
Proto-Oncogene Proteins / genetics
-
Signal Transduction / drug effects
-
Skin Neoplasms / genetics*
-
Skin Neoplasms / metabolism
-
Skin Neoplasms / pathology
-
bcl-2 Homologous Antagonist-Killer Protein / deficiency
-
bcl-2 Homologous Antagonist-Killer Protein / genetics
Substances
-
Adaptor Proteins, Signal Transducing
-
Apoptosis Regulatory Proteins
-
BCL2L11 protein, human
-
BMF protein, human
-
Bak1 protein, mouse
-
Bcl-2-Like Protein 11
-
Bcl2l11 protein, mouse
-
Membrane Proteins
-
Peptide Fragments
-
Proto-Oncogene Proteins
-
bcl-2 Homologous Antagonist-Killer Protein
-
MYO5A protein, human
-
DYNLL1 protein, human
-
Myosin Type V
-
Myosin Heavy Chains
-
Cytoplasmic Dyneins
-
DYNLL2 protein, human