The plakin protein superfamily. Depicted are all known members of the plakin family of proteins containing the plakin domain, arranged in a phylogenetic tree on the basis of the sequences of plakin domains (blue bar). Protein domains detected by SMART analysis are shown in coloured boxes ( Schultz et al., 1998).

Spectraplakin gene structure, splicing and protein isoforms. The Drosophila shot gene and the human BPAG1 gene are shown. The arrows above the line show the alternative starts of transcription (P2, P1, P3, Pe). Exons are indicated by boxes, and splicing is only shown for the alternative starts or where exons are bypassed. Different alternative transcripts are then shown below each gene. The colours of the alternative N-termini are random, but the colours of the other exons reflect the protein domains encoded, as used in Figs 1 and 2. Below these is the labelling of the different domains used in the new nomenclature: the different N-termini (2,1,3,e for the very N-termini, C for each of the two calponin homology domains), the common plakin domain (p), the plectin-repeat domain (P in shot, P1 or P2 in BPAG1), the spectrin-repeat domain, EF hands and the GAS2 domain (SG). On the left is the description of each isoform using the new nomenclature. Additional variation in the GAS2 domain for both genes and in the splicing linking the plakin domain to the spectrin repeats in shot are not shown. It is not known whether all these forms exist. For example recent northern analysis could not detect BPAG1 transcripts containing the C domains with P1, or P1 with P2 ( Leung et al., 2001b).