Also, the present study analyzed patients with relatively less advanced PH, which makes it difficult to extrapolate the findings of this study to those with advanced PH. Further, IVS motion was evaluated using a methodology that is not commonly used. However, speckletracking echocardiography is an established method of regional analysis of IVS 
motion. Indeed, the calculated intra- and interobserver reproducibility of the paradoxical IVS motion index were favorably high. Lastly, we did not conduct pathological observations in the present study. Thus, further clinicopathological studies are warranted to clarify the true mechanisms of LGE at VIPs in PH. In conclusion, the present CMR study of PH demonstrated an independent association of LGE at VIPs with early systolic paradoxical IVS motion, but not with indices of pulmonary hemodynamics and RV morphology. This suggests that LGE at VIPs is a hallmark of altered IVS motion but not of PH per se. The clinical relevance of this distinct CMR finding must be clarified in future long-term studies. As a result of its simple architecture consisting of just one type of secondary structure, the a-helical coiled coil is considered a paradigm for studies aimed at understanding the fundamental principles that govern protein stability, folding and oligomerization. Such studies have resulted in the extensive use of coiled coils for the rational design of multi-stranded structures in applications as diverse as basic research, biotechnology, nanotechnology, materials science and medicine. For example, designed two- and three-stranded coiled coils were successfully used as lead molecules to target the adenomatous polyposis coli tumor-suppressor protein implicated in colorectal cancers and to inhibit HIV infection, respectively. However, the factors that control coiled-coil folding and oligomerization are not yet well understood. Amongst such factors, “trigger” sequences are known to play an important role in coiled-coil formation. They comprise short, distinct amino-acid sequences, many of which fold into moderately stable monomeric a-helices prior to the formation of coiled-coil structures. Apparently, the function of a trigger sequence is to present key residues in a coiled coil-like conformation, which AbMole Veratramine serves as a scaffold for the recognition and in-register alignment of partner helices. Interacting helices then “zip up” along the molecule to form a stable coiled-coil structure. Several determinants that control the oligomerization state of coiled coils have been identified and studied in great detail. Major roles are played by the specific placement of hydrophobic core residues, in particular isoleucine and leucine, and their distribution generally correlates well with the oligomerization state of coiled coils. An accumulation of isoleucine and leucine residues at the heptad repeat a and d core positions, respectively, favors the formation of dimers whereas the reverse arrangement results in tetrameric structures.