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Table 3 Components of the basement membrane: See Figure 2

From: The central role of vascular extracellular matrix and basement membrane remodeling in metabolic syndrome and type 2 diabetes: the matrix preloaded

Component Constituent Chains Molecular Composition Function
Type IV Collagen: alpha 1(IV), alpha 2(IV)
alpha 3(IV)
alpha 4(IV)
alpha 5(IV)
Three alpha chains
Polygonal shaped
Network structure Provides a structural-lattice base for the attachment of other BM macromolecules such as HSPG, laminin, enactin and Fn.
Heparan sulfate proteoglycan (HSPG):
Proteoglycan (PG)
Polypeptide chain, side chains of GAGs Protein Core GAG side chains Highly anionic sulfated.
Multiple globular protein core with multiple polypeptide chains. See figure 2.
Electrostatic charge important for filtering. Especially in renal glomerulus.
Enactin – Nidogen: [31]
Structural – Adhesive Glycoprotein
Single polypeptide chain Structure:
Dumbbell-shaped sulfated glycoprotein
Bridges Laminin and Type IV collagen.
Important in assembly of the BM and changes in permselectivity properties.
Fibronectin (Fn):
Structural – Adhesive Glycoprotein
Two polypeptide chains connected by two disulfide bridges. Structural glycoprotein One of the most primitive ECM macromolecules: The first to be deposited in the embryo. Parallel to V-shaped joined by two disulfide bonds. Connecting cells with other components of the ECM, which integrates the cell into a functional unit. Very important in wound healing.
The most abundant glycoprotein in BMs. Structural – Adhesive Glycoprotein
Capillary Basement membrane lamina
A, B1, B2
First unique protein of the capillary basement membrane
One A and two B chains. Structure: Cruciform shape
Rod like structure found only in the lamina rara of capillaries
Cell attachment Assembly of the BM Stabilization of type IV Collagen
Cell-matrix attachment providing stability to the basement membrane
  1. See Figure 2