F-actin binding and bundling properties of fimbrin, a major cytoskeletal protein of microvillus core filaments
- PMID: 6894925
F-actin binding and bundling properties of fimbrin, a major cytoskeletal protein of microvillus core filaments
Abstract
Fimbrin, previously recognized as a major structural protein of the microfilament core bundles of intestinal epithelial cell microvilli, has been purified to homogeneity and characterized. It is a nearly globular monomeric protein of apparent molecular weight 68,000 and has a single calcium binding site (Kd = 9 microM), for which magnesium ions compete. Fimbrin binds to F-actin and this interaction is characterized in detail. Under our optimal binding of conditions, fimbrin induces tightly packed F-actin bundles, similar to the bundles induced by villin, another microvillus structural protein. The formation of mixed fimbrin-villin-actin bundles provides a further step toward the full in vitro reconstitution of microvillus core filaments from its purified individual components. The reconstituted fimbrin-villin-actin bundles do not display the side arms characteristic of isolated microvillus cores. These results are discussed in terms of our current understanding of the organization of the microvillus core filaments and indicate that this structure contains two bundling proteins, villin and fimbrin. The results complement previous studies and now provide a minimal biochemical characterization of all four major actin-associated structural proteins so far identified in core filaments. Three of these (villin, fimbrin, and calmodulin) are calcium-binding proteins, emphasizing the concept of calcium control over submembranous microfilament organization.
Similar articles
-
Tropomyosin distinguishes between the two actin-binding sites of villin and affects actin-binding properties of other brush border proteins.J Cell Biol. 1987 Jan;104(1):29-40. doi: 10.1083/jcb.104.1.29. J Cell Biol. 1987. PMID: 3793760 Free PMC article.
-
Reassociation of microvillar core proteins: making a microvillar core in vitro.J Cell Biol. 1989 Feb;108(2):495-502. doi: 10.1083/jcb.108.2.495. J Cell Biol. 1989. PMID: 2918023 Free PMC article.
-
Fimbrin is a cytoskeletal protein that crosslinks F-actin in vitro.Proc Natl Acad Sci U S A. 1981 Nov;78(11):6849-53. doi: 10.1073/pnas.78.11.6849. Proc Natl Acad Sci U S A. 1981. PMID: 6947259 Free PMC article.
-
Molecular architecture of the microvillus cytoskeleton.Ciba Found Symp. 1983;95:164-79. doi: 10.1002/9780470720769.ch10. Ciba Found Symp. 1983. PMID: 6342995 Review.
-
Microvillus assembly. Not actin alone.Curr Biol. 1995 Jun 1;5(6):591-3. doi: 10.1016/s0960-9822(95)00117-5. Curr Biol. 1995. PMID: 7552163 Review.
Cited by
-
Partial purification and characterization of an actin-bundling protein, band 4.9, from human erythrocytes.J Cell Biol. 1985 Mar;100(3):775-85. doi: 10.1083/jcb.100.3.775. J Cell Biol. 1985. PMID: 3882722 Free PMC article. Review.
-
Microvillus 110K-calmodulin: effects of nucleotides on isolated cytoskeletons and the interaction of the purified complex with F-actin.J Cell Biol. 1985 May;100(5):1455-65. doi: 10.1083/jcb.100.5.1455. J Cell Biol. 1985. PMID: 3157690 Free PMC article.
-
Novel espin actin-bundling proteins are localized to Purkinje cell dendritic spines and bind the Src homology 3 adapter protein insulin receptor substrate p53.J Neurosci. 2003 Feb 15;23(4):1310-9. doi: 10.1523/JNEUROSCI.23-04-01310.2003. J Neurosci. 2003. PMID: 12598619 Free PMC article.
-
Conserved genes act as modifiers of invertebrate SMN loss of function defects.PLoS Genet. 2010 Oct 28;6(10):e1001172. doi: 10.1371/journal.pgen.1001172. PLoS Genet. 2010. PMID: 21124729 Free PMC article.
-
Proteins implicated in mediating self-incompatibility-induced alterations to the actin cytoskeleton of Papaver pollen.Ann Bot. 2011 Sep;108(4):659-75. doi: 10.1093/aob/mcr022. Epub 2011 Feb 13. Ann Bot. 2011. PMID: 21320881 Free PMC article. Review.
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Other Literature Sources
