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| CONSERVATION OF THE STRUCTURE OF KERATIN INTERMEDIATE FILAMENTS - MOLECULAR MECHANISM BY WHICH DIFFERENT KERATIN MOLECULES INTEGRATE INTO PREEXISTING KERATIN INTERMEDIATE FILAMENTS DURING DIFFERENTIATION |
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| Author(s): STEINERT PM, MAREKOV LN, PARRY DAD |
| Source: BIOCHEMISTRY Volume: 32 Issue: 38 Pages: 10046-10056 Published: SEP 28 1993 |
| Times Cited: 49 References: 52 |
| Abstract: During development and differentiation, the intermediate filament component of the cytoskeleton of many cells and tissues is rebuilt by a dynamic exchange process in which one set of protein chains is replaced by another, without recourse to creation of a new network. One major example is the replacement of keratin 5/keratin 14 (K5/K14) keratin intermediate filaments (KIFs) by K1/K10 KIFs during terminal differentiation in the epidermis. The present work was undertaken to explore how this may occur. We have induced lysine-lysine cross-links with disulfosuccinimidyl tartrate in K5/K14 KIFs in order to determine the axial dimensions and relative axial alignments of the K5/K14 molecules. Many of the cross-links induced in subfilamentous oligomers containing one, two, or three molecules were also found in the intact KIF, indicating that the body of data thus generated provides physiologically relevant information on the structural organization in the KIF. A least-squares analysis using as data the positions of lysine residues involved in 23 induced cross-links has allowed the axial alignments of the various coiled-coil segments in the rod domain to be determined. Three modes of antiparallel alignment of two neighboring molecules were found: A11 (staggered by -16.7 nm), A22 (staggered by 28.8 nm), and A12 (almost in register; staggered by only 0.3 nm). Since the axial repeat length is about 1 nm less than the molecular length, the data require a fourth mode of molecule alignment, termed A(CN), in which similarly directed molecules are overlapped by the equivalent of about 5-10 residues. Interestingly, these axial alignments and dimensions are essentially identical to those adduced previously for K1/K10 KIF [Steinert, P. M., Marekov, L. N., Fraser, R. D. B., & Parry, D. A. D. (1993) J. Mol. Biol. 230, 436-452], thus indicating that the two types of KIF have conserved structures. Accordingly, our new data suggest that exchange of the K5/K14 molecules by K1/K10 molecules can occur simply because both have the same linear dimensions and axial configurations. Further work will be necessary to determine whether the lack of assembly compatibility of molecules in other IF systems is due to variations in their axial dimensions and alignments. |
| Document Type: Article |
| Language: English |
| Reprint Address: STEINERT, PM (reprint author), NIAMSD, SKIN BIOL BRANCH, BLDG 6, ROOM 425, 9000 ROCKVILLE PIKE, BETHESDA, MD 20892 USA |
Addresses:
1. MASSEY UNIV, DEPT PHYS & BIOPHYS, PALMERSTON NORTH, NEW ZEALAND |
| Publisher: AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 |
| Subject Category: Biochemistry & Molecular Biology |
| IDS Number: LZ638 |
| ISSN: 0006-2960 |
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