Evidence for export of a muscle lectin from cytosol to extracellular matrix and for a novel secretory mechanism
- Univ. of California, San Francisco (USA)
A soluble lactose-binding lectin with subunit Mr of 14,500 is believed to function by interacting with extracellular glycoconjugates, because it has been detected extracellularly by immunohistochemistry. This localization has been questioned, however, since the lectin lacks a secretion signal sequence, which challenges the contention that it is secreted. We have demonstrated externalization of this lectin from C2 mouse muscle cells by both immunoprecipitation of metabolically labeled protein and immunohistochemical localization. We further show that externalization of the lectin is a developmentally regulated process that accompanies myoblast differentiation and that the lectin codistributes with laminin in myotube extracellular matrix. Immunohistochemical localization during intermediate stages of externalization suggests that the lectin becomes concentrated in evaginations of plasma membrane, which pinch off to form labile lectin-rich extracellular vesicles. This suggests a possible mechanism for lectin export from the cytosol to the extracellular matrix.
- OSTI ID:
- 6809913
- Journal Information:
- Journal of Cell Biology; (USA), Vol. 110:5; Other Information: Databank sent to: EMBL/X51903; GENBANK/X51903; DDBJ/X51903; ISSN 0021-9525
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LECTINS
MEMBRANE TRANSPORT
AMINO ACID SEQUENCE
BIOLOGICAL LOCALIZATION
CELL DIFFERENTIATION
CELL MEMBRANES
EXTRACELLULAR SPACE
FLUORESCENCE
HEMAGGLUTININS
LABELLING
METHIONINE
MICE
MUSCLES
SULFUR ISOTOPES
TRACER TECHNIQUES
AGGLUTININS
AMINO ACIDS
ANIMALS
ANTIBODIES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
DRUGS
ISOTOPE APPLICATIONS
ISOTOPES
LIPOTROPIC FACTORS
LUMINESCENCE
MAMMALS
MEMBRANES
MOLECULAR STRUCTURE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
RODENTS
SPACE
VERTEBRATES
550201* - Biochemistry- Tracer Techniques