Maspin is an intracellular serpin that partitions into secretory vesicles and is present at the cell surface
| Autor: | James R. Erickson, Zahi M. Mouchabeck, A. Rene Tipton, Michael C. Kiefer, Philip A. Pemberton, Jason Smith, Nadine Pavloff |
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| Rok vydání: | 1998 |
| Předmět: |
0301 basic medicine
Male Cytoplasm Histology Serpin Biology Cytoplasmic Granules Epithelium 03 medical and health sciences Tumor Cells Cultured Humans Secretion Genes Tumor Suppressor Tissue Distribution Breast RNA Messenger Intestinal Mucosa Cells Cultured Serpins DNA Primers Mammary tumor 030102 biochemistry & molecular biology Endoplasmic reticulum Maspin Myoepithelial cell Membrane Proteins Proteins Subcellular localization Blotting Northern Secretory Vesicle Immunohistochemistry Cell biology 030104 developmental biology Female Anatomy Subcellular Fractions |
| Zdroj: | The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society. 45(12) |
| ISSN: | 0022-1554 |
| Popis: | The tumor suppressor maspin (mammary serpin) was originally identified as a component of human mammary epithelial cells that is downregulated as mammary tumor cells progress from the benign to the invasive and metastatic states. Maspin inhibits cellular invasion, motility, and proliferation, but its mechanism of action is currently unknown. Because the cellular machinery responsible for these processes is cytoplasmic, we have reexamined the tissue distribution and subcellular localization of maspin. We find that maspin, or a maspin-like protein, is present in many human organs, in which it localizes to epithelia. In cultured human mammary myoepithelial cells, maspin is predominantly a soluble cytoplasmic protein that associates with secretory vesicles and is present at the cell surface. In vitro assays show that the vesicle association is due to the existence of an uncleaved facultative secretion signal that allows small amounts of maspin to partition into the endoplasmic reticulum. These results demonstrate that maspin is more widespread than previously believed. The subcellular localization studies indicate that soluble intracellular and vesicle-associated maspin probably play an important role in controlling the invasion, motility, and proliferation of cells expressing it, whereas extracellular maspin may also regulate these processes in adjacent cells. |
| Databáze: | OpenAIRE |
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