2ymy | pdb_00002ymy
Structure of the murine Nore1-Sarah domain
Structural highlights
Function[RASF5_MOUSE] Potental tumor suppressor. Seems to be involved in lymphocyte adhesion by linking RAP1A activation upon T-cell receptor or chemokine stimulation to integrin activation. Isoform 2 stimulates lymphocyte polarization and the patch-like distribution of ITGAL/LFA-1, resulting in an enhanced adhesion to ICAM1. Together with RAP1A may participate in regulation of microtubule growth. The association of isoform 2 with activated RAP1A is required for directional movement of endothelial cells during wound healing (By similarity). May be involved in regulation of Ras apoptotic function. The RASSF5-STK4/MST1 complex may mediate HRAS1 and KRAS induced apoptosis.[1] Publication Abstract from PubMedTumor suppressor Nore1, its acronym coming from novel Ras effector, is one of the 10 members of the Rassf (Ras association domain family) protein family that have been identified. It is expressed as two mRNA splice variants, Nore1A and a shorter isoform, Nore1B. It forms homo- and heterocomplexes through its C-terminal SARAH (Sav/Rassf/Hpo) domain. The oligomeric state of Nore1 and other SARAH domain-containing proteins is important for their cellular activities. However, there are few experimental data addressing the structural and biophysical characterization of these domains. In this study, we show that the recombinant SARAH domain of Nore1 crystallizes as an antiparallel homodimer with representative characteristics of coiled coils. As is typical for coiled coils, the SARAH domain shows a heptad register, yet the heptad register is interrupted by two stutters. The comparisons of the heptad register of Nore1-SARAH with the primary structure of Rassf1-4, Rassf6, MST1, MST2, and WW45 indicate that these proteins have a heptad register interrupted by two stutters, too. Moreover, on the basis of the structure of Nore1-SARAH, we also generate structural models for Rassf1 and Rassf3. These models indicate that Rassf1- and Rassf3-SARAH form structures very similar to that of Nore1-SARAH. In addition, we show that, as we have previously found for MST1, the SARAH domain of Nore1 undergoes association-dependent folding. Nevertheless, the Nore1 homodimer has a lower affinity and thermodynamic stability than the MST1 homodimer, while the monomer is slightly more stable. Our experimental results along with our theoretical considerations indicate that the SARAH domain is merely a dimerization domain and that the differences between the individual sequences lead to different stabilities and affinities that might have an important functional role. Structural and Thermodynamic Characterization of Nore1-SARAH: A Small, Helical Module Important in Signal Transduction Networks.,Makbul C, Constantinescu Aruxandei D, Hofmann E, Schwarz D, Wolf E, Herrmann C Biochemistry. 2013 Feb 12;52(6):1045-54. doi: 10.1021/bi3014642. Epub 2013 Jan, 30. PMID:23331050[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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