LMNA and Hutchinson-Gilford progeria syndrome: This CaaX motif-associated phenomenon raises a question regarding whether lobulated nuclei in HGPS patient fibroblasts, expressing progerin (lamin A mutant retaining CAAX motif), are the specific feature of HGPS, or just the simple effect of large amounts of progerin accumulated at the nuclear membrane, or both; that is, the accumulation of CaaX protein (progerin) causes lobulation, which then causes further abnormalities in the chromatin structure and gene expression profile.