Protein-protein interactions between keratin polypeptides expressed in the yeast two-hybrid system.
Keratin filaments are obligatory heteropolymers of type I and type II keratin polypeptides. Specific type I/type II pairs are coexpressed in vivo. In contrast, all type I/type II pairs assemble into filaments in vitro, but the different pairs have different stabilities as demonstrated by treatment with increasing concentrations of urea. We have used the yeast two-hybrid system to analyse type I/type II interactions in a cellular context. We measured interactions between two different keratin pairs and we confirm the findings that K6+K17 form very stable heterodimers whereas K8+K18 interactions were weaker. The deletion of head domains did not reduce the strength of type I/type II interactions. Rather, the affinities were increased and the differences between the two pairs were retained in headless mutants. These findings argue against a major role of the head domains in directing heterodimer interactions and in defining heterodimer stabilities.
Schnabel
J
J
Department of Biochemistry, Max-Planck-Institute for Biophysical Chemistry, D-37070 Göttingen, Germany.
Weber
K
K
Hatzfeld
M
M
D007382:Intermediate Filaments / Q000235:genetics / Q000378:metabolism*; D007633:Keratins / Q000235:genetics / Q000378:metabolism*; D008967:Molecular Biology / Q000379:methods; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017384:Sequence Deletion
D010455:Peptides; D007633:Keratins