title: Emerin-prelamin A interplay in human fibroblasts.
abstract: BACKGROUND
  Emerin is a nuclear envelope protein that contributes to nuclear architecture, chromatin structure, and gene expression through its interaction with various nuclear proteins. In particular, emerin is molecularly connected with the nuclear lamina, a protein meshwork composed of lamins and lamin-binding proteins underlying the inner nuclear membrane. Among nuclear lamina components, lamin A is a major emerin partner. Lamin A, encoded by the LMNA gene (lamin A/C gene), is produced as a precursor protein (prelamin A) that is post-transcriptionally modified at its C-terminal region where the CaaX motif triggers a sequence of modifications, including farnesylation, carboxymethylation, and proteolytic cleavage by ZMPSTE 24 (zinc metalloproteinase Ste24) metalloproteinase. Impairment of the lamin A maturation pathway causing lamin A precursor accumulation is linked to the development of rare diseases such as familial partial lipodystrophy, MADA (mandibuloacral dysplasia), the Werner syndrome, Hutchinson-Gilford progeria syndrome and RD (restrictive dermopathy).
  
  
  RESULTS
  In the present study, we show that emerin and different prelamin A forms influence each other's localization. We show that the accumulation of non-farnesylated as well as farnesylated carboxymethylated lamin A precursors in human fibroblasts modifies emerin localization. On the contrary, emerin absence at the inner nuclear membrane leads to unprocessed (non-farnesylated) prelamin A aberrant localization only. Moreover, we observe that the restoration of emerin expression in emerin-null cells induces the recovery of non-farnesylated prelamin A localization.
  
  
  CONCLUSIONS
  These results indicate that emerin-prelamin A interplay influences nuclear organization. This finding may be relevant to the understanding of laminopathies.
authors.affiliation: IGM-CNR, Unit of Bologna c/o IOR, Bologna, Italy. ccapanni@area.bo.cnr.it
authors.forename: Cristina
authors.initials: C
authors.lastname: Capanni
authors.forename: Rosalba
authors.initials: R
authors.lastname: Del Coco
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Mattioli
authors.forename: Daria
authors.initials: D
authors.lastname: Camozzi
authors.forename: Marta
authors.initials: M
authors.lastname: Columbaro
authors.forename: Elisa
authors.initials: E
authors.lastname: Schena
authors.forename: Luciano
authors.initials: L
authors.lastname: Merlini
authors.forename: Stefano
authors.initials: S
authors.lastname: Squarzoni
authors.forename: Nadir Mario
authors.initials: NM
authors.lastname: Maraldi
authors.forename: Giovanna
authors.initials: G
authors.lastname: Lattanzi