Smooth Muscle Adherens Junctions Associated Proteins are Stable at the Cell Periphery During Relaxation and Activation

Authors

Thomas J. Eddinger, Marquette UniversityFollow
Jessen D. Schiebout, Marquette University
Darl R. Swartz, Purdue University - Main Campus

Document Type

Article

Language

eng

Format of Original

9 p.

Publication Date

12-1-2005

Publisher

American Physiological Society

Source Publication

American Journal of Physiology - Cell Physiology

Source ISSN

1522-1563

Abstract

This study was performed to determine the stability of the adherens junction (AJ)-associated proteins at the smooth muscle cell (SMC) plasma membrane during relaxing and activating conditions. Dog stomach, ileum, colon, and trachea tissues were stored in Ca²⁺-free PSS or regular PSS or were activated in 10 μM carbachol in PSS before rapid freezing. The tissues were subsequently sectioned and immunoreacted using antibodies for vinculin, talin, fibronectin, and caveolin to determine their cellular distribution in these tissues under these conditions. In all four tissues and under all three conditions, the distribution of these four proteins remained localized to the periphery of the cell. In transverse tissue sections, the AJ-associated proteins formed a distinct punctate pattern around the periphery of the SMCs at the plasma membrane. These domains alternated with the caveolae (as identified by the presence of caveolin). In longitudinal tissue sections, the AJ-associated proteins formed continuous tracks or staves, while the caveolae remained punctate in this dimension as well. Caveolin is not present in the tapered ends of the SMCs, where the AJ-associated proteins appear continuous around the periphery. Densitometry of the fluorophore distribution of these proteins showed no shift in their localization from the SMC periphery when the tissues were relaxed or when they were activated before freezing. These results suggest that under physiologically relaxing and activating conditions, AJ-associated proteins remain stably localized at the plasma membrane.

Comments

American Journal of Physiology - Cell Physiology, Vol. 289, No. 5 (December 1, 2005): C1379-C1387. DOI.

Recommended Citation

Eddinger, Thomas J.; Schiebout, Jessen D.; and Swartz, Darl R., "Smooth Muscle Adherens Junctions Associated Proteins are Stable at the Cell Periphery During Relaxation and Activation" (2005). Biological Sciences Faculty Research and Publications. 220.
https://epublications.marquette.edu/bio_fac/220