Structures and Dynamic Motion of Laminin-1 As Observed by Atomic Force Microscopy

Abstract

Laminins are a family of multifunctional extracellular matrix glycoproteins that play important roles in the development and maintenance of tissue organization via their interactions with cells and other extracellular matrix proteins. To understand the structural basis of laminins' functions, we examined the motion of laminin-1 (Ln-1) in physiological buffers using atomic force microscopy. While many Ln-1 molecules assumed the expected cruciform structure, unexpected dynamic movements of the Ln-1 arms were observed in aqueous environments. These dynamic movements of the Ln-1 arms may contribute to the diversity of laminin functions.

Arrangement of Type IV Collagen and Laminin on Substrates with Controlled Density of –OH Groups

“…[34][35][36] The structure of Lam molecules has been extensively studied during the recent decades employing electron microscopy and also AFM. 16,37,38 Consistent with this studies an appearance of cross-shaped molecules with approximate size of 70-100 nm (depending on their conformation) might be expected as the maximal dimensions of the completely extended cruciform Lam molecule is 125 nm long, 72 nm wide, and 2.2 nm thick. 37 The phase images on Figure 3A show Lam distribution after adsorption from solution of a high concentration (20 mg/mL).…”

“…16,37,38 Consistent with this studies an appearance of cross-shaped molecules with approximate size of 70-100 nm (depending on their conformation) might be expected as the maximal dimensions of the completely extended cruciform Lam molecule is 125 nm long, 72 nm wide, and 2.2 nm thick. 37 The phase images on Figure 3A show Lam distribution after adsorption from solution of a high concentration (20 mg/mL). Note, although such concentration is not optimal for AFM imaging, it is the one used for the cellular investigations.…”

“…Also, the drying process could lead to lateral reorganization of the adsorbed protein layer at the air-liquid interface, and this process seems to be favored on very hydrophilic surfaces because of the absence of protein-surface interactions strong enough to prevent protein relaxation during water release. 39 Nevertheless, independently of the complex arrangements of Lam on our surfaces some cross-shaped structures that resemble single molecules seen on mica 37 can be sparsely observed on X OH = 0.3 and X OH = 1 surfaces (Fig. 3A, arrowheads), suggesting a protein deposition in a near-natural configuration.…”

Varieties of imaging with scanning probe microscopes

“…1b were in air, whereas the laminin molecule shown in Fig. 2a was under aqueous solution, with three of its four arms moving in these successive images (23).…”

High‐Speed Atomic Force Microscopy of Biomolecules in Motion

“…Dynamic movements of the arms of laminin-1 that might contribute to the diversity of laminin functions were observed (Chen et al, 1998). Calcium-mediated structural changes of native nuclear pore complexes such as the opening and closing of individual nuclear baskets were observed, indicating that cytoplasmic plugging and unplugging of the complex is insensitive to calcium in the absence of ATP (Stoffler et al, 1999).…”