Table 2.

Basement Membrane Scaffold Inter-Component Binding Interactions

Bond	Ligand Domain(s)	Nature of Interaction(s)	References
laminin - laminin	LN domains of the α, β and γ short arms interact with corresponding LN domains.	Polymerization (crit. conc. ≈ 0.1 μM) requiring three short arm LN domains. Individual LN+LEa	[10, 16–19]
nidogen - laminin	Nidogen-G3 to Lmγ1(LEb3), γ2, γ3	Nd1-Lm111, KD ≤ 1 nM Nd2-Lm111, KD ≤ 1 nM	[134, 138]
agrin - laminin	Agrin NtA to Lm-γ1 coiled-coil	Lm-111: KD ≈ 2 nM	[79, 151]
laminins - heparin/heparan sulfate	LG domains; α1, unprocessed α2, α4 >processed α2, LN domains of Lmα1>Lmα2>Lmα3B (Lmα5 does not bind to heparin)	a1) Lmα1LG4–5 binds to heparin with KD = 22 nM (elutes ~0.3 M NaCl), 38 nM for α1LN in E1′. (a2) rLm-211 (LG+LN) elutes from heparin column at 0.16 and 0.33 M NaCl while rLm211ΔLG1–5 (LN) elutes at 0.09 M. b) LN protein fragment elution off heparin column with 0.27 (α1), 0.24 (α2), 0.14 (α3B) and 0.0 (α5) M NaCl in 50 mM Tris, pH 7.4.	[17, 179, 199, 200]
nidogen - collagen IV	Nd (G3>G2 domains) to collagenous chain	Nd1-ColIV, KD < 1 nM < 1 nM Nd2-ColIV, KD	[134, 138]
nidogen - perlecan	Nd1-G2 and Nd2 to perlecan-domain IV	KD ≈ 10 nM	[142, 191]
perlecan - fibronectin	Perlecan domain IV	KD ≈ 10 nM	[142]
perlecan - laminin	Perlecan domain-I (likely heparan sulfate chains) to laminin LG and LN domains	Likely relatively low affinity and specificity.	[142]
perlecan - collagen IV	Perlecan domain-I (likely heparan sulfate chains) to collagen-IV	Likely relatively low affinity and specificity.	[142]
perlecan - heparin	Perlecan domain IV	see above	[142]
nidogen - fibulin 2		KD ≤ 0.5 nM	[138]
collagen IV - collagen IV	NC1 - NC1 7S lateral (collagenous)	high affinity dimerization of collagen trimeric NC1 domains (forms “hexamer”) overlap of four triple helical ends covalently stabilized by disulfides side-by-side associations that help form a network	[6, 107, 109, 112, 120, 201]