Overexpression of a family of RPEL proteins modifies cell shape.

Proteins containing RPEL motifs (e.g., MAL) are important in the regulation of gene expression by the actin cytoskeleton. Screening the ENSEMBL database for RPEL proteins identified four additional proteins that contain RPEL motifs and nuclear localisation sequences, three of which (RPEL-A, RPEL-B and RPEL-C) are expressed in adult mouse tissues with different expression profiles. The mRNAs encoding RPEL-B and RPEL-C were subject to alternative splicing. Expression of these genes in cells indicated that they had a marked effect on cell shape. Furthermore, when expressed with a nuclear localised actin all of the different forms became restricted to the nucleus.