Spectraplakins and their isoforms
| Isoform | Tissue | Description |
| BPAG1e; BPAG1 | Major epithelial variant | Contains plakin domain conserved in related plakin family of proteins; lacking functional actin-binding domain at N terminus |
| BPAG1a1; BPAG1n4 | Major neuronal variant; predominantly in sensory neurons | Contains unique short N-terminal region mediating actin binding |
| BPAG1a2 | Major neuronal variant; predominantly expressed in tissues affected in dt mice | Contains N-terminal transmembrane domain |
| BPAG1a3 | Isoform 3 is not expressed in appreciable levels in the brain but is the primary isoform expressed in the lung | Contains N-terminal conserved myristoylation motif |
| BPAG1b1, b2, and b3 | Predominant in muscle | Similar to BPAG1a1–3 but contains a 2,000–amino acid sequence coding for a novel PRD domain before the spectrin repeats |
| ACF7/MACF1a1 | Ubiquitously expressed | Contains a 100-kb uncharacterized sequence between the first exon and exons encoding the first CH domain |
| ACF7/MACF1a2 | Ubiquitously expressed | |
| ACF7/MACF1a3 | Ubiquitously expressed | Contains only CH2 domain and lacks CH1 |
| MACF1b | Ubiquitously expressed with especially high levels in the lung; localizes to Golgi complex | Identical to MACF1a but contains a region with plectin or plakin repeats in the middle of the molecule |
| MACF1c | Lacks N-terminal actin-binding domain | |
| VAB-10A | Restricted to fibrous organelles | Resembles BPAG1e and ends with the PRD |
| VAB-10B | Diffuse distribution in epidermis and muscle | Resembles BPAG1a |
| Shot A | Represents predominant isoform in central nervous system | Original shot isoform contains an actin-binding domain, a plakin domain, a series of spectrin repeats, and a GAR MT-binding domain |
| Shot B | Localizes at cell–cell junctions in the zonula adherens in embryonic epidermis and follicle epithelium | Contains a long stretch of plakin repeats inserted between the plakin domain and the spectrin repeats; note that the presence of plakin repeats is surprising, given that in other organisms, this repeat mediates interaction with IFs and Drosophila do not have cytoplasmic IFs |
| Shot C | – | Lacks the first CH domain |
| Shot D | – | Lacks both CH domains |
| Isoform | Tissue | Description |
| BPAG1e; BPAG1 | Major epithelial variant | Contains plakin domain conserved in related plakin family of proteins; lacking functional actin-binding domain at N terminus |
| BPAG1a1; BPAG1n4 | Major neuronal variant; predominantly in sensory neurons | Contains unique short N-terminal region mediating actin binding |
| BPAG1a2 | Major neuronal variant; predominantly expressed in tissues affected in dt mice | Contains N-terminal transmembrane domain |
| BPAG1a3 | Isoform 3 is not expressed in appreciable levels in the brain but is the primary isoform expressed in the lung | Contains N-terminal conserved myristoylation motif |
| BPAG1b1, b2, and b3 | Predominant in muscle | Similar to BPAG1a1–3 but contains a 2,000–amino acid sequence coding for a novel PRD domain before the spectrin repeats |
| ACF7/MACF1a1 | Ubiquitously expressed | Contains a 100-kb uncharacterized sequence between the first exon and exons encoding the first CH domain |
| ACF7/MACF1a2 | Ubiquitously expressed | |
| ACF7/MACF1a3 | Ubiquitously expressed | Contains only CH2 domain and lacks CH1 |
| MACF1b | Ubiquitously expressed with especially high levels in the lung; localizes to Golgi complex | Identical to MACF1a but contains a region with plectin or plakin repeats in the middle of the molecule |
| MACF1c | Lacks N-terminal actin-binding domain | |
| VAB-10A | Restricted to fibrous organelles | Resembles BPAG1e and ends with the PRD |
| VAB-10B | Diffuse distribution in epidermis and muscle | Resembles BPAG1a |
| Shot A | Represents predominant isoform in central nervous system | Original shot isoform contains an actin-binding domain, a plakin domain, a series of spectrin repeats, and a GAR MT-binding domain |
| Shot B | Localizes at cell–cell junctions in the zonula adherens in embryonic epidermis and follicle epithelium | Contains a long stretch of plakin repeats inserted between the plakin domain and the spectrin repeats; note that the presence of plakin repeats is surprising, given that in other organisms, this repeat mediates interaction with IFs and Drosophila do not have cytoplasmic IFs |
| Shot C | – | Lacks the first CH domain |
| Shot D | – | Lacks both CH domains |