Coordinated folding and association of the LIN-2, -7 (L27) domain. An obligate heterodimerization involved in assembly of signaling and cell polarity complexes.
LIN-2, -7 (L27) homology domains are putative protein-protein interaction modules found in several scaffold proteins involved in the assembly of polarized cell-signaling structures. These specific interaction pairs are well conserved across metazoan species, from worms to man. We have expressed and purified L27 domains from multiple species and find that certain domains from proteins such as Caenorhabditis elegans LIN-2 and LIN-7 can specifically heterodimerize. Biophysical analysis of interacting L27 domains demonstrates that the domains interact with a 1:1 stoichiometry. Circular dichroism studies reveal that the domains appear to function as an obligate heterodimer; individually the domains are largely unfolded, but when associated they show a significant increase in helicity, as well as a cooperative unfolding transition. These novel obligate interacting pairs are likely to play a key role in regulating the organization of signaling proteins at polarized cell structures.
Harris
Baruch Z
BZ
Program in Biological Sciences, University of California, San Francisco, California 94143-0450, USA.
Venkatasubrahmanyam
Shivkumar
S
Lim
Wendell A
WA
D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins; D019281:Dimerization; D015801:Helminth Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017510:Protein Folding; D051381:Rats
D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; C099173:LIN-7 protein, C elegans; C097978:Lin-2 protein, C elegans; D008565:Membrane Proteins