Heterogeneity in Lymphocyte Spectrin Distribution: Ultrastructural Identification of a New Spectrin-Rich Cytoplasmic Structure

• Published in: The Journal of cell biology Vol. 106; no. 1; pp. 97 - 109
• Main Authors: Black, Jennifer D., Koury, Stephen T., Bankert, Richard B., Repasky, Elizabeth A.
• Format: Journal Article
• Language: English
• Published: New York, NY Rockefeller University Press 01-01-1988; The Rockefeller University Press
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; Carrier Proteins - metabolism; Cell aggregates; Cell Compartmentation - drug effects; Cell lines; Cell Membrane - metabolism; Cell membranes; Cells; Cells, Cultured; Chromaffin cells; Cytoplasm - metabolism; Cytoplasm - ultrastructure; Epithelial cells; Erythrocytes; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Holoproteins; Hot Temperature; Humans; Immunoenzyme Techniques; Leukocytes; Lymphocytes; Lymphocytes - ultrastructure; Microfilament Proteins - metabolism; Microscopy, Electron; Other proteins; Phorbol Esters - pharmacology; Plasma spectra; Proteins; Spectrin - metabolism; Thymus Gland - ultrastructure; Human; Spectrin; Cell culture; Hybrid cell; Immunocytochemistry; Cell differentiation; Enzyme immunoassay; Proteins; Transmission electron microscopy; Ultrastructure; Plasma membrane; Immunofluorescence; Localization; Lymphocyte
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.106.1.97

Spectrin-like proteins are found in a wide variety of non-erythroid cells where they generally occur in the cell cortex near the plasma membrane. To determine the intracellular distribution of α-spectrin (α-fodrin) in lymphocytes, we have developed an immunoperoxidase method to localize this protein at the ultrastructural level. Of considerable interest, particularly with regard to our efforts to determine the function of spectrin in this cell type, was the finding that its subcellular localization and its relationship with the plasma membrane can vary dramatically. Based on its position in the cell, α-spectrin can occur in two forms in lymphocytes: one that associates closely with the plasma membrane and another that occurs at some distance from the cell periphery, either as a single large aggregate or as several smaller ones. The single large aggregate of spectrin is a stable feature in a number of lymphocyte cell lines and hybrids which were used to examine its ultrastructural characteristics. A previously undescribed cellular structure, consisting of a meshwork of spectrin filaments and membranous vesicles, was identified in these cells. This structure could be induced to dissipate in response to membrane perturbants (e.g., hyperthermia and phorbol esters, known effectors of lymphocyte function and differentiation) and the patterns resulting from the redistribution of spectrin were a reflection of those observed routinely in lymphocytes in situ. The correlation between naturally occurring spectrin localization patterns and those seen after membrane perturbation suggested the possibility that spectrin distribution is indicative of particular maturation stages or functional states in lymphocytes. The implications of these findings with regard to the role of spectrin in lymphocyte function are discussed.