The Bi-Functional Organization of Human Basement Membranes
نویسندگان
چکیده
The current basement membrane (BM) model proposes a single-layered extracellular matrix (ECM) sheet that is predominantly composed of laminins, collagen IVs and proteoglycans. The present data show that BM proteins and their domains are asymmetrically organized providing human BMs with side-specific properties: A) isolated human BMs roll up in a side-specific pattern, with the epithelial side facing outward and the stromal side inward. The rolling is independent of the curvature of the tissue from which the BMs were isolated. B) The epithelial side of BMs is twice as stiff as the stromal side, and C) epithelial cells adhere to the epithelial side of BMs only. Side-selective cell adhesion was also confirmed for BMs from mice and from chick embryos. We propose that the bi-functional organization of BMs is an inherent property of BMs and helps build the basic tissue architecture of metazoans with alternating epithelial and connective tissue layers.
منابع مشابه
Gene structure and functional analysis of the mouse nidogen-2 gene: nidogen-2 is not essential for basement membrane formation in mice.
Nidogens are highly conserved proteins in vertebrates and invertebrates and are found in almost all basement membranes. According to the classical hypothesis of basement membrane organization, nidogens connect the laminin and collagen IV networks, so stabilizing the basement membrane, and integrate other proteins. In mammals two nidogen proteins, nidogen-1 and nidogen-2, have been discovered. N...
متن کاملAn organizing function of basement membranes in the developing nervous system
The basement membranes (BMs) of the nervous system include (a) the pial BM that surrounds the entire CNS, (b) the BMs that outline the vascular system of the CNS and PNS and (c) the BMs that are associated with Schwann cells. We previously found that isolated BMs are bi-functionally organized, whereby the two surfaces have different compositional, biomechanical and cell adhesion properties. To ...
متن کاملBasement Membranes in the Worm: A Dynamic Scaffolding that Instructs Cellular Behaviors and Shapes Tissues.
The nematode worm Caenorhabditis elegans has all the major basement membrane proteins found in vertebrates, usually with a smaller gene family encoding each component. With its powerful forward genetics, optical clarity, simple tissue organization, and the capability to functionally tag most basement membrane components with fluorescent proteins, C. elegans has facilitated novel insights into t...
متن کاملOntogenesis of glomerular basement membrane: structural and functional properties
Protein A-gold immunocytochemistry was applied in combination with morphometrical approaches to reveal the alpha 1(IV), alpha 2(IV), and alpha 3(IV) chains of type IV collagen as well as entactin on renal basement membranes, particularly on the glomerular one, during maturation. The results have indicated that a heterogeneity between renal basement membranes appears during the maturation proces...
متن کاملBasement membranes.
Basement membranes are thin, specialized extracellular matrices surrounding most tissues in all metazoans. The compositions and functions of basement membranes have generally been well conserved throughout the subkingdom. Genetic analyses of basement membrane components in C. elegans have provided insights into their assembly and functions during development. Immuno- or GFP-tagged localization ...
متن کامل