FIGURE 5.

GIP130 is a FILIP1L isoform having features of a structural protein that is preferentially expressed in striated muscle. A, the primary structure of GIP130 is shown in one-letter code. The predicted coiled-coiled region and canonical leucine zippers are highlighted with gray and black backgrounds, respectively. B, shown are the exon-intron structures of pre-mRNA of GIP130 (GenBank^TM accession number AF514867) and FILIP1L-102 (GenBank^TM accession BC027860) transcribed from FILIP1L at 3q12.1 and exon sequence of I20. C, ³²P-labeled cDNAs representing both GIP130 and FILIP1L-102 (I20 probe) or GIP130 (exon I–IV probe) or β-actin mRNAs were used to subsequently probe a premade Northern blot of poly(A⁺) RNA from the indicated human tissues. Shown are 5-day (I20), 8-day (exons I–IV), and 0.5-day (β-actin) exposures at −70 °C, respectively. The arrowheads and numbers indicate the positions and sizes (kb) of identified mRNA species, whereas the bars and numbers similarly denote RNA markers. D, lysates (50 μg) of HEK 293 cells transfected with either pRK-c-Myc-GIP130 (GIP130), pRK5-c-Myc-FILIP1L-102 (FILIP1L-102), or pRK5-c-Myc vector (control) were analyzed by Western blot with the indicated antibodies. E, schematic alignment of primary structures (bars) of GIP130 and FILIP1L-102 polypeptides expressed in D. Gray shading and black boxes represent coiled-coils and leucine zippers, respectively.