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 |