Strong association of bovine IgM with microvilli and their microfilament core from 13762 ascites tumor cells.

Abstract

Microfilament cores, obtained by extracting 13762 mammary ascites tumor cell microvilli with Triton X-100, contain a major glycoprotein migrating at an apparent molecular weight of 80 kDa by dodecyl sulfate-polyacrylamide gel electrophoresis. The 80-kDa component is a disulfide-linked multimer, as demonstrated by velocity sedimentation and agarose-acrylamide gel electrophoresis analyses under nonreducing conditions. This 80-kDa species is not metabolically labeled, as is a minor 80-kDa glycoprotein found in the cores, membranes, and an isolated transmembrane complex with actin. Antibodies prepared against the 80-kDa glycoprotein react strongly with bovine IgM and more weakly with rat IgM. These antibodies were used to demonstrate that the 80-kDa component is present in microvilli, microvillar microfilament cores, and microvillar membranes only if the microvilli are prepared in the presence of calf serum. The 80-kDa component, purified by velocity sedimentation in dodecyl sulfate, reacts with anti-rat IgM by immunoblot analyses. Moreover, immunoprecipitation of detergent extracts of microvilli with anti-rat IgM specifically sediments the 80-kDa component. The 80-kDa glycoprotein fractionates with the actin-containing transmembrane complex prepared by gel filtration of Triton-solubilized microvillar membranes. These results indicate that the disulfide-linked, multi-meric 80-kDa component is bovine IgM, which binds strongly to a cell-surface component of the microvilli, and is indirectly associated with the microfilament cores. Thus, the IgM provides a marker by which the transmembrane complexes to the microfilaments can be identified.

• Authors: X H Ye, T N Metcalf 3rd, D M Andrews, C A Carraway, K L Carraway
• Journal: Experimental cell research (Exp Cell Res) Vol. 182 Issue 1 Pg. 160-72 (May 1989) ISSN: 0014-4827 [Print] United States
• PMID: 2714400 (Publication Type: Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Culture Media
• Immunoglobulin M
• Membrane Glycoproteins

Topics

• Animals
• Blotting, Western
• Cattle
• Cell Membrane (metabolism)
• Culture Media
• Immunoglobulin M (metabolism)
• In Vitro Techniques
• Membrane Glycoproteins (metabolism)
• Microvilli (metabolism, ultrastructure)
• Molecular Weight
• Precipitin Tests
• Protein Binding
• Rats