Table III. Comparison of protein abundance quantification in targeted LC-MS/MS experiments (MRM) versus data-dependent LC-MS/MS experiments. Changes in protein abundance in response to long-term (5 days) dDAVP (D) versus vehicle (V). Values are Mean ± S.E. of log2 (D/V).
| Protein name (gene symbol, Refseq) | Annotation (from Swiss-Prot) | Targeted LC-MS/MS Log2 (D/V) | Non-targeted LC-MS/MS Log2 (D/V) |
|---|---|---|---|
| Aquaporin 2 (Aqp2, NP_033829) | Vasopressin-regulated water-specific channel that provides the plasma membranes of renal collecting duct with high permeability to water, thereby permitting water to move in the direction of an osmotic gradient. | 3.3 ± 0.4* | 4.4 ± 0.5* |
| MON2 homolog (Mon2, NP_700444) | May be required for traffic between late Golgi and early endosomes. | 3.6 ± 1.1* | 2.8 ± 0.3* |
| MAL2 proteolipid protein (Mal2, NP_849251) | Member of the machinery of polarized transport. Required for the indirect transcytotic route at the step of the egress of the transcytosing cargo from perinuclear endosomes in order for it to travel to the apical surface via a raft-dependent pathway. | 0.7 ± 0.1 | 1.0 ± 0.2* |
| Dystonin isoform a/b (Dst, NP_598594; NP_604443) | Cytoskeletal linker protein. Anchors keratin-containing intermediate filaments to the inner plaque of hemi-desmosomes. The proteins may self-aggregate to form filaments or a two-dimensional mesh. | 0.1 ± 0.1 | 0.9 ± 0.2* |
| Sodium/hydrogen exchanger regulatory factor 1, NHERF1 (Slc9a3r1, NP_036160) | Scaffold protein that connects plasma membrane proteins with members of the ezrin/moesin/radixin family and thereby helps to link them to the actin cytoskeleton and to regulate their surface expression. Necessary for cAMP-mediated phosphorylation and inhibition of SLC9A3. May enhance Wnt signaling. | 0.7 ± 0.4* | 0.5 ± 0.2 |
| Lysosomal membrane glycoprotein 2 isoform 2 (Lamp2, NP_034815) | May function in protection of the lysosomal membrane from autodigestion, maintenance of the acidic environment of the lysosome, adhesion when expressed on the cell surface (plasma membrane), and inter- and intracellular signal transduction. Protects cells from the toxic effects of methylating mutagens. | 0.4 ± 0.5 | 0.5 ± 0.5 |
| RAB7 (Rab7, NP_033031) | Involved in late endocytic transport. Contributes to the maturation of phagosomes (acidification). | 0.2 ± 0.1 | 0.1 ± 0.1 |
| Na+/K+-ATPase a1 subunit (Atp1a1, NP_659149) | Catalytic component of the active enzyme that catalyzes the hydrolysis of ATP coupled with the exchange of sodium and potassium ions across the plasma membrane. This action creates the electrochemical gradient of sodium and potassium ions, providing the energy for active transport of various nutrients. | 0.3 ± 0.2 | −0.2 ± 0.1 |
| Tight junction protein 1 or ZO-1 (Tjp1, NP_033412) | The N-terminal [portion] may be involved in transducing a signal required for tight junction assembly, while the C-terminal [portion] may have specific properties of tight junctions. The alpha domain might be involved in stabilizing junctions. | −0.1 ± 0.0 | −0.2 ± 0.0* |
* Statistically significant by two-tailed t-test against log2(1) (p < 0.05).