title: Control of concanavalin A receptor mobility by cytoplasmic actin in human tumour cells.
abstract: Tissue culture monolayers of seven human intracranial tumours comprising 2 astrocytomas, 3 meningiomas, 1 secondary squamous cell carcinoma and 1 secondary adenocarcinoma were examined by a double immunofluorescent staining technique to demonstrate Concanavalin A (Con A) surface receptors and cytoplasmic actin in the same cell. Tumour cells, treated with fluoresceinisothiocyanate-labelled Con A (FITC-Con A) showed staining in cell margins or in a random distribution over the cell surface. Incubating the cells with FITC-Con A at 37 degrees for increasing periods of time resulted first in staining of clusters and later of perinuclear globules. Cells, pretreated with 4% paraformaldehyde at 4 degrees for 10 min or with cytochalasin B at 37 degrees for 30 min showed staining restricted to cell margins. In the cytochalasin B-treated cells, the peripheral staining was in the form of coarse clusters. Double fluorochrome studies showed that the anti-actin antibody (AAA) staining occurred in sites closely related to those stained by FITC-Con A both in untreated as well as in cytochalasin B-treated cells. The findings suggest that Con A receptors, as an example of a stable cell membrane determinant in human tumour cells, are associated with actin and that their mobility on the cell surface is dependent on an intact cytoplasmic actin system.
mesh_terms: D000199:Actins / Q000032:analysis*; D000230:Adenocarcinoma / Q000032:analysis; D001254:Astrocytoma / Q000032:analysis; D001932:Brain Neoplasms / Q000032:analysis*; D002294:Carcinoma, Squamous Cell / Q000032:analysis; D003078:Colchicine / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D003593:Cytoplasm / Q000032:analysis*; D005455:Fluorescent Antibody Technique; D006801:Humans; D066298:In Vitro Techniques; D008579:Meningioma / Q000032:analysis; D011952:Receptors, Concanavalin A / Q000032:analysis* / Q000187:drug effects; D011955:Receptors, Drug / Q000032:analysis*
chemical_list: D000199:Actins; D011952:Receptors, Concanavalin A; D011955:Receptors, Drug; D003571:Cytochalasin B; D003078:Colchicine