Table 2.
The most common IN/OUT-domains found in the predicted membrane protein sequences
| SMART ID | Description | IN/OUT | No. of hits | % Single span |
| S_TKc | Serine/Threonine protein kinases, catalytic domain | IN | 691 | 50 |
| IG | Immunoglobulin | OUT | 522 | 66 |
| TyrKc | Tyrosine kinase, catalytic domain | IN | 487 | 54 |
| RING | Ring finger | IN | 410 | 45 |
| IGc2 | Immunoglobulin C-2 type | OUT | 301 | 67 |
| CA | Cadherin repeats | OUT | 271 | 53 |
| FN3 | Fibronectin type 3 domain | OUT | 246 | 66 |
| CLECT | C-type lectin (CTL) or carbohydrate-recognition domain (CRD) | OUT | 235 | 85 |
| LRRCT | Leucine rich repeat C-terminal domain | OUT | 213 | 74 |
| t_SNARE | Helical region found in SNAREs | IN | 210 | 99 |
| C2 | Protein kinase C conserved region 2 (CalB) | IN | 179 | 68 |
| cNMP | Cyclic nucleotide- monophosphate binding domain | IN | 178 | 2 |
| EGF_CA | Calcium-binding EGF-like domain | OUT | 175 | 67 |
| IGc1 | Immunoglobulin C-Type | OUT | 171 | 55 |
| GPS | G-protein–coupled receptor proteolytic site domain | OUT | 169 | 1 |
The percentage of domain hits in single-spanning proteins, as determined by the constrained predictions, is also indicated.