Characterization of Human Alpha-Dystrobrevin Isoforms in HL-60 Human Promyelocytic Leukemia Cells Undergoing Granulocytic Differentiation

Abstract

The biochemical properties and spatial localization of the protein alpha-dystrobrevin and other isoforms were investigated in cells of the human promyelocytic leukemia line HL-60 granulocytic differentiation as induced by retinoic acid (RA). Alpha-dystrobrevin was detected both in the cytosol and the nuclei of these cells, and a short isoform (gamma-dystrobrevin) was modified by tyrosine phosphorylation soon after the onset of the RA-triggered differentiation. Varying patterns of distribution of alpha-dystrobrevin and its isoforms could be discerned in HL-60 promyelocytes, RA-differentiated mature granulocytes, and human neutrophils. Moreover, the gamma-dystrobrevin isoform was found in association with actin and myosin light chain. The results provide new information about potential involvement of alpha-dystrobrevin and its splice isoforms in signal transduction in myeloid cells during induction of granulocytic differentiation and/or at the commitment stage of differentiation or phagocytic cells.

Characterization of a novel Dp71 dystrophin-associated protein complex (DAPC) present in the nucleus of HeLa cells: Members of the nuclear DAPC associate with the nuclear matrix

“…Besides, Dp71, the complex is composed, at least, of β-dystroglycan, α1-and βdystrobrevin and nNOS. Previously, the presence of Dp71 and several DAPC components in the nuclei of different cell types has been described [17,19,20]. The nuclear distribution of Dp71 has been observed in cultured hippocampal neurons [35] and the PC12 cell line [36,37].…”

“…The nuclear distribution of Dp71 has been observed in cultured hippocampal neurons [35] and the PC12 cell line [36,37]. Additionally, α-dystrobrevin was found in the nuclei of the human cell line HL-60 [19] whereas β-dystrobrevin was observed in the nuclear compartment of hippocampal pyramidal neurons [17]. Furthermore, the nuclear localization of α-, β-and γ1syntrophin has been described in HeLa cells [20].…”

“…An additional complication in understanding the diversity of DAPC functions has emerged from the evidence showing that several DAPC components are present in the nuclear compartment, such as α-and β-dystrobrevins [17,19] and α-, β-and γ1-syntrophins [20]. Moreover, by using green fluorescence protein-Dp71 protein fusions (GFP-Dp71), we have previously shown that Dp71 splicing variants containing amino acids encoded by exon 71 and/or 78 distribute predominantly in the nuclei of HeLa cells [21].…”

α-Dystrobrevin distribution and association with other proteins in human promyelocytic NB4 cells treated for granulocytic differentiation

“…It was displayed that -DBs are expressed not only in muscular cells, but also in human epithelial cervical cancer cells (HeLa) and human promyelocytic leukemia cells (HL-60), but the functions in non muscle cells are still not clear [10,11]. Since the phosphorylation state of DB-gamma changed during the differentiation process after HL-60 cell treatment with all-trans retinoic acid (ATRA), it was suggested that this modulates the association of -DB with other proteins, possibly resulting in a different ability of the proteins to participate in cellular signaling [11].…”

“…Since the phosphorylation state of DB-gamma changed during the differentiation process after HL-60 cell treatment with all-trans retinoic acid (ATRA), it was suggested that this modulates the association of -DB with other proteins, possibly resulting in a different ability of the proteins to participate in cellular signaling [11].…”