|PROSITE documentation PDOC51841|
Intermediate filaments (IFs) constitute a major structural element of metazoan cells. They build two distinct systems: one inside the nucleus attached to the inner membrane, and one that is cytoplasmic, which connects intercellular junctional complexes situated at the plasma membrane with the outer nuclear membrane. In both cases, their major function is assumed to be that of a mechanical stress absorber and an integrating device for the entire cytoskeleton. In the nucleus, the IF system is assembled from lamins, which together with an ever increasing number of associated transmembrane and chromatin-binding proteins constitute the nuclear lamina. Despite the large diversity among IF proteins, they all share a similar structural building plan, with a long central α-helical 'rod' domain (see <PDOC00198>) that is flanked by non-α-helical N- and C-terminal end domains called 'head' and 'tail', respectively. Lamins exhibit a highly conserved globular C-terminal lamin-tail domain (LTD) which has the immunoglobulin (Ig) fold (see <PDOC50835>). Invertebrate cytoplasmic IFs share sequence similarity with nuclear lamins and also contain a C-terminal tail domain with homology to the LTD [1,2,3].
Domains homologous to the LTD have been detected in several uncharacterized proteins from phylogenetically diverse bacteria and two archaea, Methanosarcina and Halobacterium. In several bacterial proteins, the LTD cooccurs with membrane-associated hydrolases of the metallo-β-lactamase, synaptojanin, and calcineurin-like phosphoesterase superfamilies. In other secreted or periplasmic bacterial proteins, the LTDs are associated with oligosaccharide-binding domains or are present as multiple tandem repeats in a single protein. These associations suggest a potential role for the prokaryotic LTDs in tethering proteins to the membrane or membrane-associated structures. In contrast to the bacterial homologs, all animal LTDs are closely related and are contained in proteins with a stereotypic architecture. The precursor of the animal LTD might have been acquired via horizontal gene transfer from bacteria relatively late in the evolution of the eukaryotic crown group. Subsequent to this acquisition, a coiled-coil domain, derived from preexisting intermediate filament coil-coils, might have been fused to the N-termini of the LTD .
The LTD domain could be involved both in protein and DNA binding .
Th LTD domain adopts an Ig-like fold of type s (see <PDB:1IFR>). It consists of a 2-layered sandwich of 9 anti-parallel β-strands arranged in two β-sheets with a Greek key topology. One of the sheets has five β-strands while the other has four. Seven of the 9 strands are present in the classical Ig fold topology [4,5].
Some proteins known to contain a LTD domain are listed below:
The profile we developed covers the entire LTD domain.Last update:
August 2017 / First entry.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Herrmann H. Baer H. Kreplak L. Strelkov S.V. Aebi U.|
|Title||Intermediate filaments: from cell architecture to nanomechanics.|
|Source||Nat. Rev. Mol. Cell Biol. 8:562-573(2007).|
|2||Authors||Mans B.J. Anantharaman V. Aravind L. Koonin E.V.|
|Title||Comparative genomics, evolution and origins of the nuclear envelope and nuclear pore complex.|
|Source||Cell Cycle 3:1612-1637(2004).|
|3||Authors||Weber K. Riemer D. Dodemont H.|
|Title||Aspects of the evolution of the lamin/intermediate filament protein family: a current analysis of invertebrate intermediate filament proteins.|
|Source||Biochem. Soc. Trans. 19:1021-1023(1991).|
|4||Authors||Krimm I. Oestlund C. Gilquin B. Couprie J. Hossenlopp P. Mornon J.-P. Bonne G. Courvalin J.-C. Worman H.J. Zinn-Justin S.|
|Title||The Ig-like structure of the C-terminal domain of lamin A/C, mutated in muscular dystrophies, cardiomyopathy, and partial lipodystrophy.|
|5||Authors||Ruan J. Xu C. Bian C. Lam R. Wang J.-P. Kania J. Min J. Zang J.|
|Title||Crystal structures of the coil 2B fragment and the globular tail domain of human lamin B1.|
|Source||FEBS Lett. 586:314-318(2012).|
|6||Authors||Huesken K. Wiesenfahrt T. Abraham C. Windoffer R. Bossinger O. Leube R.E.|
|Title||Maintenance of the intestinal tube in Caenorhabditis elegans: the role of the intermediate filament protein IFC-2.|