Table 2:
Proteins Unique to the Apical Compartment
| Uniprot Identification Number | Protein* (n = 17) | Average Spectral Count† | Location‡ |
|---|---|---|---|
| O95436 | Sodium-dependent phosphate transport protein 2B | 24 | Membrane |
| P06576 | ATP synthase subunit β, mitochondrial | 19 | Mitochondion |
| P09525 | Annexin A4 | 17 | Unknown |
| P00558 | Phosphoglycerate kinase 1 | 17 | Cytoplasm |
| P08758 | Annexin A5 | 15 | Unknown |
| O75874 | Isocitrate dehydrogenase [NADP] cytoplasmic | 13 | Cytoplasm |
| Q8WXI7 | Mucin-16§ | 13 | Secreted |
| P15941 | Mucin-1§ | 13 | Secreted |
| P00352 | Retinal dehydrogenase 1 | 12 | Cytoplasm |
| P40199 | Carcinoembryonic antigen-related cell adhesion molecule 6 | 12 | Secreted |
| P07237 | Protein disulfide-isomerase | 11 | Secreted |
| O14818 | Proteasome subunit α type-7 | 6 | Cytoplasm |
| P60660 | Myosin light polypeptide 6§ | 5 | Exosome |
| P27105 | Erythrocyte band 7 integral membrane protein§ | 5 | Exosome |
| P28072 | Proteasome subunit β type-6 | 4 | Cytoplasm |
| P49720 | Proteasome subunit β type-3 | 4 | Cytoplasm |
| P61160 | Actin-related protein 2 | 3 | Cytoplasm |
*
Listed proteins were present in all apical secretions and no basolateral secretions. Of the 69 proteins identified in all apical secretions but in fewer than three basal secretions, 31 proteins were associated with fewer than 2 peptides in basolateral secretions.
†
Spectral count calculated and normalized based on ProteoIQ; average based on values from all cell cultures.
‡
Location based on Uniprot and SecretomeP databases.
§
Identified in exosomes from in vitro primary differentiated airway epithelial cell cultures in a previous study (27).