The isolated intestinal microvillus cytoskeleton (core) consists of four major proteins: actin, villin, fimbrin and brush border myosin-I. These proteins can assemble in vitro into structures resembling native microvillus cores. Of these components, villin and brush border myosin-I show tissue-specific expression, so they may be involved in the morphogenesis of intestinal microvilli. When introduced into cultured cells that normally lack the protein, villin induces a reorganization of the actin filaments to generate large surface microvilli. Here we examine the consequences of microinjecting brush border myosin-I either alone or together with villin into cultured fibroblasts. Injection of brush border myosin-I has no discernible effect on the overall morphology of the cells, but does become localized to either normal or villin-induced microvilli and other surface structures containing an actin cytoskeleton. Since some endogenous myosin-Is have been found associated with cytoplasmic vesicles, these results show that brush border myosin-I has a domain that specifically targets it to the plasma membrane in both intestinal and cultured cell systems. Ultrastructural examination of microvilli on control cultured cells revealed that they contain a far more highly ordered bundle of microfilaments than had been previously appreciated. The actin filaments in microvilli of villin-injected cells appeared to be more tightly cross-linked when examined by thin-section electron microscopy. In intestinal microvilli, the core bundle is separated from the plasma membrane by about 30 nm due to the presence of brush border myosin-I.(ABSTRACT TRUNCATED AT 250 WORDS)
Brush border myosin-I microinjected into cultured cells is targeted to actin-containing surface structures
M. Footer, A. Bretscher; Brush border myosin-I microinjected into cultured cells is targeted to actin-containing surface structures. J Cell Sci 1 June 1994; 107 (6): 1623–1631. doi: https://doi.org/10.1242/jcs.107.6.1623
Download citation file:
Advertisement
Cited by
Call for papers: Cell Biology of Motors
(update)-MotorCFPExtended.jpg?versionId=3964)
Journal of Cell Science is pleased to welcome submissions for consideration for an upcoming special issue, Cell Biology of Motors. The deadline for submitting articles has been extended to 30 August 2022.
Find out more about our preprint policies
-bioRxiv.jpg?versionId=3964)
Last year, 47% of the manuscripts published in Journal of Cell Science were posted as preprints on bioRxiv. You can find our preprint policies here.
Cell scientist to watch: Jeremy Carlton
(update)-CSTW.png?versionId=3964)
Journal of Cell Science caught up with Jeremy Carlton, who established his independent research group in 2012 at the Division of Cancer Studies, King's College London. His lab is currently seconded to the Francis Crick Institute and is investigating membrane and organelle remodelling during cell division. This year, he was awarded the Hooke Medal by the British Society for Cell Biology (BSCB).
The FocalPlane Network
-FocalPlaneNetwork.png?versionId=3964)
The FocalPlane Network is an international directory of researchers with microscopy expertise including developers, imaging scientists and bioimage analysts. It is designed to help you find speakers, committee members, reviewers and potential collaborators. Find out more about the FocalPlane Network.
The Corona Files
-Mole.png?versionId=3964)
“We were not ready for a pandemic, despite decades of warnings.”
Our resident insectivore, Mole, continues his latest series – The Corona Files. This time, Mole reflects on what we have learned from the pandemic.