Abstract
Dedicator-of-cytokinesis (DOCK), a family of guanine-nucleotide exchange factors (GEFs), comprises four subfamilies, named from A to D. DOCK-D comprises DOCK9, DOCK10, and DOCK11. The GEF activity involves translocation from the cytoplasm to the plasma membrane (PM), as assessed by the transfection of tagged proteins. However, the cellular localization of endogenous DOCK proteins is poorly understood. In this paper, to gain a better understanding of the role of the DOCK-D proteins, we studied their distribution between cytosol and nucleoplasm in 11 cell lines. DOCK-D proteins were distributed with variable cytosolic or nuclear predominance, although the latter was common for DOCK9 and DOCK11. These results suggest that the DOCK-D proteins may perform new nuclear functions, which remain to be discovered. Furthermore, we found that DOCK10 levels are increased by interleukin-4 (IL-4) in B-cell lymphoid neoplasms other than chronic lymphocytic leukemia (CLL) such as mantle cell lymphoma and diffuse large B-cell lymphoma. We also found evidence for an induction of the cytosolic levels of DOCK10 by IL-4 in CLL. Finally, we obtained a valid DOCK10 antiserum for immunofluorescence (IF) microscopy that, as an antibody against the hemagglutinin (HA) tag, marked PM ruffles and filopodia in HeLa cells with inducible expression of HA-DOCK10.
Highlights
We found that IL-4 induces the expression of DOCK10 in lymphoid neoplasms such as mantle cell lymphoma and DLBCL, and we confirmed that IL-4 induces cytoplasmic levels of DOCK10 in chronic lymphocytic leukemia (CLL)
A new nuclear function of DOCK1 has recently been discovered in the uterus, consisting of the nuclear import of the autoimmune regulator (AIRE), a mechanism that plays a role in decidualization [24]
Proteins is rare or frequent, we carried out biochemical studies in cytosolic and nuclear fractions of 11 cell lines, eight of which are hematopoietic and three are fibroblastlike/epithelial, using three commercial Abs directed against total DOCK9, DOCK10, and
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Dedicator-of-cytokinesis (DOCK) proteins are the products of a family of 11 genes that act as guanine-nucleotide exchange factors (GEFs) for Rho GTPases [1]. They are characterized by a central CZH-1 domain that interacts with phospholipids of the plasma membrane (PM), and a C-terminal CZH2 domain that harbors the GEF activity. DOCK proteins are grouped into four subfamilies, A to D.
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