Biosynthesis and Deposition of a Noncovalent Laminin-Heparan Sulfate Proteoglycan Complex and Other Basal Lamina Components by a Human Malignant Cell Line

Syndecan-1 (SDC1) is a cell surface heparan sulfate proteoglycan (HSPG), which regulates various signaling pathways controlling the proliferation and migration of malignant mesothelioma and other types of cancer. We have previously shown that SDC1 can translocate to the nucleus in mesothelioma cells through a tubulin-dependent transport mechanism. However, the role of nuclear SDC1 is largely unknown. Here, we performed co-immunoprecipitation (Co-IP) of SDC1 in a mesothelioma cell line to identify SDC1 interacting proteins. The precipitates contained a large number of proteins, indicating the recovery of protein networks. Proteomic analysis with a focus on nuclear proteins revealed an association with pathways related to cell proliferation and RNA synthesis, splicing and transport. In support of this, the top RNA splicing candidates were verified to interact with SDC1 by Co-IP and subsequent Western blot analysis. Further loss- and gain-of-function experiments showed that SDC1 influences RNA levels in mesothelioma cells. The results identify a proteomic map of SDC1 nuclear interactors in a mesothelioma cell line and suggest a previously unknown role for SDC1 in RNA biogenesis. The results should serve as a fundament for further studies to discover the role of nuclear SDC1 in normal and cancer cells of different origin.

Download Full-text

Effects of heparan sulfate proteoglycan syndecan-4 on the insulin secretory response in a mouse pancreatic β-cell line, MIN6

Molecular and Cellular Endocrinology ◽

10.1016/j.mce.2017.10.008 ◽

2018 ◽

Vol 470 ◽

pp. 142-150 ◽

Cited By ~ 2

Author(s):

Iwao Takahashi ◽

Shuhei Yamada ◽

Koji Nata

Keyword(s):

Heparan Sulfate ◽

Cell Line ◽

Heparan Sulfate Proteoglycan ◽

Secretory Response ◽

Sulfate Proteoglycan ◽

Pancreatic Β Cell ◽

Β Cell ◽

Insulin Secretory Response

Download Full-text

Aggregates of acetylcholine receptors are associated with plaques of a basal lamina heparan sulfate proteoglycan on the surface of skeletal muscle fibers.

The Journal of Cell Biology ◽

10.1083/jcb.97.5.1396 ◽

1983 ◽

Vol 97 (5) ◽

pp. 1396-1411 ◽

Cited By ~ 133

Author(s):

M J Anderson ◽

D M Fambrough

Keyword(s):

Skeletal Muscle ◽

Neuromuscular Junction ◽

Heparan Sulfate ◽

Basal Lamina ◽

Acetylcholine Receptors ◽

Muscle Fibers ◽

Muscle Cells ◽

Heparan Sulfate Proteoglycan ◽

Sulfate Proteoglycan ◽

Skeletal Muscle Fibers

Hybridoma techniques have been used to generate monoclonal antibodies to an antigen concentrated in the basal lamina at the Xenopus laevis neuromuscular junction. The antibodies selectively precipitate a high molecular weight heparan sulfate proteoglycan from conditioned medium of muscle cultures grown in the presence of [35S]methionine or [35S]sulfate. Electron microscope autoradiography of adult X. laevis muscle fibers exposed to 125I-labeled antibody confirms that the antigen is localized within the basal lamina of skeletal muscle fibers and is concentrated at least fivefold within the specialized basal lamina at the neuromuscular junction. Fluorescence immunocytochemical experiments suggest that a similar proteoglycan is also present in other basement membranes, including those associated with blood vessels, myelinated axons, nerve sheath, and notochord. During development in culture, the surface of embryonic muscle cells displays a conspicuously non-uniform distribution of this basal lamina proteoglycan, consisting of large areas with a low antigen site-density and a variety of discrete plaques and fibrils. Clusters of acetylcholine receptors that form on muscle cells cultured without nerve are invariably associated with adjacent, congruent plaques containing basal lamina proteoglycan. This is also true for clusters of junctional receptors formed during synaptogenesis in vitro. This correlation indicates that the spatial organization of receptor and proteoglycan is coordinately regulated, and suggests that interactions between these two species may contribute to the localization of acetylcholine receptors at the neuromuscular junction.

Download Full-text

Localization of type IV collagen, laminin, heparan sulfate proteoglycan, and fibronectin to the basal lamina of basement membranes.

The Journal of Cell Biology ◽

10.1083/jcb.95.1.340 ◽

1982 ◽

Vol 95 (1) ◽

pp. 340-344 ◽

Cited By ~ 322

Author(s):

G W Laurie ◽

C P Leblond ◽

G R Martin

Keyword(s):

Basement Membrane ◽

Heparan Sulfate ◽

Basal Lamina ◽

Type Iv Collagen ◽

Heparan Sulfate Proteoglycan ◽

Basement Membranes ◽

Enamel Organ ◽

Sulfate Proteoglycan ◽

Type Iv ◽

Membrane Region

Electron microscopic immunostaining of rat duodenum and incisor tooth was used to examine the location of four known components of the basement-membrane region: type IV collagen, laminin, heparan sulfate proteoglycan, and fibronectin. Antibodies or antisera against these substances were localized by direct or indirect peroxidase methods on 60-microns thick slices of formaldehyde-fixed tissues. In the basement-membrane region of the duodenal epithelium, enamel-organ epithelium, and blood-vessel endothelium, immunostaining for all four components was observed in the basal lamina (also called lamina densa). The bulk of the lamina lucida (rara) was unstained, but it was traversed by narrow projections of the basal lamina that were immunostained for all four components. In the subbasement-membrane fibrous elements or reticular lamina, immunostaining was confined to occasional "bridges" extending from the epithelial basal-lamina to that of adjacent capillaries. The joint presence of type IV collagen, laminin, heparan sulfate proteoglycan, and fibronectin in the basal lamina indicates that these substances do not occur in separate layers but are integrated into a common structure.

Download Full-text