ABSTRACT
Histone deacetylase 6 (HDAC6), a predominantly cytoplasmic protein deacetylase, participates in a wide range of cellular processes through its deacetylase activity. However, the diverse functions of HDAC6 cannot be fully elucidated with its known substrates. In an attempt to explore the substrate diversity of HDAC6, we performed quantitative proteomic analyses to monitor changes in the abundance of protein lysine acetylation in response to HDAC6 deficiency. We identified 107 proteins with elevated acetylation in the liver of HDAC6 knockout mice. Three cytoplasmic proteins, including myosin heavy chain 9 (MYH9), heat shock cognate protein 70 (Hsc70), and dnaJ homolog subfamily A member 1 (DNAJA1), were verified to interact with HDAC6. The acetylation levels of these proteins were negatively regulated by HDAC6 both in the mouse liver and in cultured cells. Functional studies reveal that HDAC6-mediated deacetylation modulates the actin-binding ability of MYH9 and the interaction between Hsc70 and DNAJA1. These findings consolidate the notion that HDAC6 serves as a critical regulator of protein acetylation with the capability of coordinating various cellular functions.
Subject(s)
Animals , Mice , Acetylation , Actins , Chemistry , Metabolism , Cell Line , Chromatography, High Pressure Liquid , HSC70 Heat-Shock Proteins , Metabolism , HSP40 Heat-Shock Proteins , Metabolism , Histone Deacetylase 6 , Histone Deacetylases , Metabolism , Isotope Labeling , Liver , Metabolism , Lysine , Metabolism , Mice, Inbred C57BL , Mice, Knockout , Microscopy, Confocal , Nonmuscle Myosin Type IIA , Metabolism , Protein Binding , Proteomics , Substrate Specificity , Tandem Mass SpectrometryABSTRACT
The study was purposed to investigate the expression and function of non-muscle myosin heavy chain-IIA (NMMHC-IIA) in Fechtner syndrome in order to explore the pathologic changes of kindy disease and the mechanism of granulocyte inclusion body formation. NMMHC-IIA levels in granulocytes were analyzed by Western-blot, the expressions of NMMHC-IIA, IIB in HEK-293 cells were detected by RT-PCR and were analyzed by co-immunoprecipitation. The results indicated that the IIA/beta-actin ratio for Fechtner syndrome granulocytes was (0.35 +/- 0.12), and obviously decreased as compared with that of normal control (0.87 +/- 0.18) (p < 0.01). The IIA and IIB expressed higher in HEK-293 cells. The interaction of IIA and IIB was confirmed by co-immunoprecipitation in HEK-293 cells. It is concluded that dominant-negative effect of NMMHC-IIA is involved in the formation of inclusion bodies. IIA and IIB show obvious interaction, IIB partly compensates the IIA defect derived from MYH9 mutations, and may delay or prevent the development of clinically relevant abnormalities.
Subject(s)
Humans , Blood Platelet Disorders , Genetics , Metabolism , Pathology , Cell Line , Granulocytes , Pathology , Inclusion Bodies , Pathology , Kidney , Cell Biology , Embryology , Metabolism , Mutation , Nonmuscle Myosin Type IIA , Genetics , Metabolism , Physiology , Nonmuscle Myosin Type IIB , Genetics , Metabolism , Physiology , Syndrome , Thrombocytopenia , Genetics , Metabolism , PathologyABSTRACT
The term MYH9-related disorders indicates a group of autosomal dominant illnesses, formerly known as May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome and Epstein syndrome, caused by mutations of MYH9, the gene encoding for the heavy chain of non-muscle myosin IIA (NMMHC-IIA). We experienced a family with macrothrombocytopenia without leukocyte inclusion. A 5-year-old girl was found to have macrothrombocytopenia incidentally. Her father also had macrothromtocytopenia, but had been suffering from hearing loss and chronic renal failure. Meticulous search by light and electron microscopy failed to detect leukocyte inclusions. To our knowledge, these cases seem to be the first description of autosomal dominant Epstein giant platelet syndrome in Korea.