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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

Structure:

Polygonal shaped

Network structure Provides a structural-lattice base for the attachment of other BM macromolecules such as HSPG, laminin, enactin and Fn.

Perlecan:

Heparan sulfate proteoglycan (HSPG):

Proteoglycan (PG)

Polypeptide chain, side chains of GAGs

Protein Core GAG side chains Highly anionic sulfated.

Structure:

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.

Laminin:

The most abundant glycoprotein in BMs. Structural – Adhesive Glycoprotein

CABLIN: NEW

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