| Identifier | Protein names | Gene names | Cross reference refseq | Length | Species |
| P09118 | Uricase; EC 1.7.3.3; Urate oxidase; | Uox; | NP_446220.1; | 303 | rat |
| P29598 | Urokinase-type plasminogen activator; U-plasminogen activator; uPA; EC 3.4.21.73; [Cleaved into: Urokinase-type plasminogen activator long chain A; Urokinase-type plasminogen activator short chain A; Urokinase-type plasminogen activator chain B]; | Plau; | NULL | 432 | rat |
| P27590 | Uromodulin; Tamm-Horsfall urinary glycoprotein; THP; [Cleaved into: Uromodulin, secreted form]; | Umod; | NP_058778.1;XP_006230169.1; | 644 | rat |
| Q5I0I5 | U6 snRNA phosphodiesterase; EC 3.1.4.-; | Usb1; | NP_001014035.1; | 267 | rat |
| Q3T1I3 | Usher syndrome type-1C protein-binding protein 1; USH1C-binding protein 1; | Ushbp1; | NP_001028859.1; | 680 | rat |
| Q63665 | Upstream stimulatory factor 2; Major late transcription factor 2; Upstream transcription factor 2; | Usf2; | NP_112401.1; | 346 | rat |
| Q8K3K1 | Usherin; Usher syndrome type IIa protein homolog; Usher syndrome type-2A protein homolog; | Ush2a; | NULL | 1512 | rat |
| Q9JJW3 | Up-regulated during skeletal muscle growth protein 5; Diabetes-associated protein in insulin-sensitive tissues; | Usmg5; Dapit; | NP_598228.1;XP_008766441.1;XP_008773622.1; | 58 | rat |
| P41542 | General vesicular transport factor p115; Protein USO1 homolog; Transcytosis-associated protein; TAP; Vesicle-docking protein; | Uso1; Vdp; | NP_062252.1; | 959 | rat |
| P97689 | Urea transporter 1; Solute carrier family 14 member 1; Urea transporter B; UT-B; Urea transporter, erythrocyte; | Slc14a1; UT11 UT3; | NP_062219.2; | 384 | rat |
| Q62668 | Urea transporter 2; Solute carrier family 14 member 2; Urea transporter, kidney; | Slc14a2; Ut2; | NP_001103740.1;NP_062220.2;NP_808877.2; | 929 | rat |
| P17559 | Uteroglobin; Clara cell phospholipid-binding protein; CCPBP; Clara cells 10 kDa secretory protein; CC10; PCB-binding protein; Secretoglobin family 1A member 1; | Scgb1a1; Cc10 Ugb Utg; | NP_037183.1; | 96 | rat |
| Q8R5K5 | Probable U3 small nucleolar RNA-associated protein 11; U3 snoRNA-associated protein 11; UTP11-like protein; | Utp11l; | NULL | 253 | rat |
| A2RRU3 | U3 small nucleolar RNA-associated protein 15 homolog; | Utp15; | NP_001101117.1;XP_006231898.1;XP_008758893.1;XP_008758894.1;XP_008758895.1; | 528 | rat |
| Q765I2 | Urotensin-2B; Urotensin II-related peptide; Urotensin IIB; U-IIB; UIIB; Urotensin-2 domain-containing protein; | Uts2b; Urp Uts2d; | NP_937766.1; | 118 | rat |
| Q9QZQ4 | Urotensin-2; Urotensin II; U-II; UII; | Uts2; | NP_062033.1; | 123 | rat |
| D3ZND0 | UV-stimulated scaffold protein A; | Uvssa; | NP_001128030.1;XP_006251383.1;XP_006251385.1;XP_006251386.1;XP_006251387.1; | 720 | rat |
| Q5PQX0 | UDP-glucuronic acid decarboxylase 1; EC 4.1.1.35; UDP-glucuronate decarboxylase 1; UGD; UXS-1; | Uxs1; | NP_647552.1; | 420 | rat |
| Q63ZY7 | Protein UXT; Ubiquitously expressed transcript protein; | Uxt; | NP_001006983.1;XP_006256673.1; | 157 | rat |
| Q5J3K9 | Vomeronasal type-1 receptor A14; | V1ra14; | NP_001008898.1; | 339 | rat |
