Structural highlights
Function
[MYO7B_MOUSE] Myosins are actin-based motor molecules with ATPase activity. Their highly divergent tails are presumed to bind to membranous compartments, which would be moved relative to actin filaments. As part of the intermicrovillar adhesion complex/IMAC plays a role in epithelial brush border differentiation, controlling microvilli organization and length. May link the complex to the actin core bundle of microvilli.[UniProtKB:Q6PIF6] [ANS4B_MOUSE] As part of the intermicrovillar adhesion complex/IMAC plays a role in epithelial brush border differentiation, controlling microvilli organization and length. Plays a role in assembly of the complex (By similarity). May play a role in cellular response to endoplasmic reticulum stress (PubMed:22589549).[UniProtKB:Q8N8V4][1]
Publication Abstract from PubMed
Brush border microvilli are actin-based protrusions lining the apical surface of epithelial cells in intestines and proximal tubules of kidneys. While brush border microvilli resemble the relatively well-characterized stereocilia of hair cells, the mechanistic basis of tip-link complex organization in microvilli is poorly understood. Here, we have biochemically and structurally characterized the following pairs of interactions: protocadherin 24 and Harmonin (also known as USH1C or AIE-75), Harmonin and myosin VIIb (MYO7B), Harmonin and ANKS4B, and ANKS4B and MYO7B. We show that Harmonin, ANKS4B, and MYO7B form a stable ternary complex for anchoring microvilli tip-link cadherins. Despite having only Harmonin in common, the microvilli and the stereocilia tip-link complexes are formed via strikingly similar interaction modes. These results not only provide insight into the mechanistic bases of brush border microvilli formation and maintenance but may also be valuable for understanding some gut and/or kidney diseases caused by perturbations of brush border microvilli structures.
Mechanistic Basis of Organization of the Harmonin/USH1C-Mediated Brush Border Microvilli Tip-Link Complex.,Li J, He Y, Lu Q, Zhang M Dev Cell. 2016 Jan 25;36(2):179-89. doi: 10.1016/j.devcel.2015.12.020. PMID:26812017[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Sato Y, Hatta M, Karim MF, Sawa T, Wei FY, Sato S, Magnuson MA, Gonzalez FJ, Tomizawa K, Akaike T, Yoshizawa T, Yamagata K. Anks4b, a novel target of HNF4alpha protein, interacts with GRP78 protein and regulates endoplasmic reticulum stress-induced apoptosis in pancreatic beta-cells. J Biol Chem. 2012 Jun 29;287(27):23236-45. doi: 10.1074/jbc.M112.368779. Epub, 2012 May 15. PMID:22589549 doi:http://dx.doi.org/10.1074/jbc.M112.368779
- ↑ Li J, He Y, Lu Q, Zhang M. Mechanistic Basis of Organization of the Harmonin/USH1C-Mediated Brush Border Microvilli Tip-Link Complex. Dev Cell. 2016 Jan 25;36(2):179-89. doi: 10.1016/j.devcel.2015.12.020. PMID:26812017 doi:http://dx.doi.org/10.1016/j.devcel.2015.12.020
