| U3 small nucleolar RNA-associated protein 6 homolog (Multiple hat domains protein) | Utp6 Mhat | Q8VCY6 | 1 |
| U4/U6 small nuclear ribonucleoprotein Prp31 (Pre-mRNA-processing factor 31) (U4/U6 snRNP 61 kDa protein) (Protein 61K) | Prpf31 Prp31 | Q8CCF0 | 1 |
| U4/U6 small nuclear ribonucleoprotein Prp4 (U4/U6 snRNP 60 kDa protein) (WD splicing factor Prp4) | Prpf4 | Q9DAW6 | 1 |
| U6 snRNA-associated Sm-like protein LSm1 | Lsm1 | Q8VC85 | 1 |
| U6 snRNA-associated Sm-like protein LSm2 (Protein G7b) (snRNP core Sm-like protein Sm-x5) | Lsm2 G7b | O35900 | 1 |
| U6 snRNA-associated Sm-like protein LSm3 | Lsm3 | P62311 | 1 |
| U7 snRNA-associated Sm-like protein LSm10 | Lsm10 | Q8QZX5 | 1 |
| UBA-like domain-containing protein 1 | Ubald1 Fam100a | Q6P3B2 | 1 |
| UbiA prenyltransferase domain-containing protein 1 (EC 2.5.1.-) | Ubiad1 | Q9DC60 | 1 |
| Ubinuclein-2 | Ubn2 Kiaa2030 | Q80WC1 | 1 |
| Ubiquitin carboxyl-terminal hydrolase (EC 3.4.19.12) | Usp32 | F8VPZ3 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 10 (EC 3.4.19.12) (Deubiquitinating enzyme 10) (Ubiquitin thioesterase 10) (Ubiquitin-specific-processing protease 10) | Usp10 Kiaa0190 Ode-1 Uchrp | P52479 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 12 (EC 3.4.19.12) (Deubiquitinating enzyme 12) (Ubiquitin thioesterase 12) (Ubiquitin-hydrolyzing enzyme 1) (Ubiquitin-specific-processing protease 12) | Usp12 Ubh1 | Q9D9M2 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 16 (EC 3.4.19.12) (Deubiquitinating enzyme 16) (Ubiquitin thioesterase 16) (Ubiquitin-specific-processing protease 16) | Usp16 | Q99LG0 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 24 (EC 3.4.19.12) (Deubiquitinating enzyme 24) (Ubiquitin thioesterase 24) (Ubiquitin-specific-processing protease 24) | Usp24 | B1AY13 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 28 (EC 3.4.19.12) (Deubiquitinating enzyme 28) (Ubiquitin thioesterase 28) (Ubiquitin-specific-processing protease 28) | Usp28 Kiaa1515 | Q5I043 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 30 (EC 3.4.19.12) (Deubiquitinating enzyme 30) (Ubiquitin thioesterase 30) (Ubiquitin-specific-processing protease 30) (Ub-specific protease 30) | Usp30 | Q3UN04 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 36 (EC 3.4.19.12) (Deubiquitinating enzyme 36) (Ubiquitin thioesterase 36) (Ubiquitin-specific-processing protease 36) | Usp36 Kiaa1453 | B1AQJ2 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 38 (EC 3.4.19.12) (Deubiquitinating enzyme 38) (Ubiquitin thioesterase 38) (Ubiquitin-specific-processing protease 38) | Usp38 | Q8BW70 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 42 (EC 3.4.19.12) (Deubiquitinating enzyme 42) (Ubiquitin thioesterase 42) (Ubiquitin-specific-processing protease 42) | Usp42 | B2RQC2 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 48 (EC 3.4.19.12) (Deubiquitinating enzyme 48) (Ubiquitin thioesterase 48) (Ubiquitin-specific-processing protease 48) | Usp48 Kiaa4202 | Q3V0C5 | 1 |
| Ubiquitin carboxyl-terminal hydrolase 8 (EC 3.4.19.12) (Deubiquitinating enzyme 8) (Ubiquitin isopeptidase Y) (mUBPy) (Ubiquitin thioesterase 8) (Ubiquitin-specific-processing protease 8) | Usp8 Kiaa0055 Ubpy | Q80U87 | 1 |
| Ubiquitin D (Diubiquitin) (Ubiquitin-like protein FAT10) | Ubd Fat10 | P63072 | 1 |
| Ubiquitin domain-containing protein 1 | Ubtd1 | Q91WB7 | 1 |
| Ubiquitin domain-containing protein 2 | Ubtd2 | Q6PGH0 | 1 |
| Ubiquitin thioesterase OTU1 (EC 3.4.19.12) | Yod1 | Q8CB27 | 1 |
| Ubiquitin thioesterase OTUB2 (EC 3.4.19.12) (Deubiquitinating enzyme OTUB2) (OTU domain-containing ubiquitin aldehyde-binding protein 2) (Otubain-2) (Ubiquitin-specific-processing protease OTUB2) | Otub2 | Q9CQX0 | 1 |
| Ubiquitin thioesterase Zranb1 (EC 3.4.19.12) (Zinc finger Ran-binding domain-containing protein 1) | Zranb1 Trabid | Q7M760 | 1 |
| Ubiquitin-associated and SH3 domain-containing protein B (EC 3.1.3.48) (Cbl-interacting protein p70) (Suppressor of T-cell receptor signaling 1) (STS-1) (T-cell ubiquitin ligand 2) (TULA-2) (Tyrosine-protein phosphatase STS1/TULA2) | Ubash3b Sts1 | Q8BGG7 | 1 |
| Ubiquitin-associated domain-containing protein 1 (UBA domain-containing protein 1) (E3 ubiquitin-protein ligase subunit KPC2) (Kip1 ubiquitination-promoting complex protein 2) | Ubac1 Kpc2 Ubadc1 | Q8VDI7 | 1 |
| Ubiquitin-conjugating enzyme E2 E3 (EC 6.3.2.19) (UbcM2) (Ubiquitin carrier protein E3) (Ubiquitin-conjugating enzyme E2-23 kDa) (Ubiquitin-protein ligase E3) | Ube2e3 Ubce4 Ubcm2 | P52483 | 1 |
| Ubiquitin-conjugating enzyme E2 J1 (EC 6.3.2.19) (Non-canonical ubiquitin-conjugating enzyme 1) (NCUBE-1) | Ube2j1 Ncube1 | Q9JJZ4 | 1 |
| Ubiquitin-conjugating enzyme E2 Q1 (EC 6.3.2.19) (Ubiquitin carrier protein Q1) (Ubiquitin-protein ligase Q1) | Ube2q1 Ube2q | Q7TSS2 | 1 |
| Ubiquitin-conjugating enzyme E2 Z (EC 6.3.2.19) (Uba6-specific E2 conjugating enzyme 1) (Use1) (Ubiquitin carrier protein Z) (Ubiquitin-protein ligase Z) | Ube2z D11Moh35 | Q3UE37 | 1 |
| Ubiquitin-fold modifier-conjugating enzyme 1 (Ufm1-conjugating enzyme 1) | Ufc1 | Q9CR09 | 1 |
| Ubiquitin-like modifier-activating enzyme 1 (Ubiquitin-activating enzyme E1) (Ubiquitin-activating enzyme E1 X) (Ubiquitin-like modifier-activating enzyme 1 X) | Uba1 Sbx Ube1 Ube1ax Ube1x | Q02053 | 1 |
| Ubiquitin-like modifier-activating enzyme ATG7 (ATG12-activating enzyme E1 ATG7) (Autophagy-related protein 7) (APG7-like) (mAGP7) (Ubiquitin-activating enzyme E1-like protein) | Atg7 Apg7l | Q9D906 | 1 |
| Ubiquitin-like protein 5 | Ubl5 | Q9EPV8 | 1 |
| UDP-GalNAc:beta-1,3-N-acetylgalactosaminyltransferase 1 (Beta-1,3-GalNAc-T1) (EC 2.4.1.79) (Beta-1,3-galactosyltransferase 3) (Beta-1,3-GalTase 3) (Beta3Gal-T3) (Beta3GalT3) (b3Gal-T3) (Beta-3-Gx-T3) (Galactosylgalactosylglucosylceramide beta-D-acetyl-galactosaminyltransferase) (Globoside synthase) (UDP-N-acetylgalactosamine:globotriaosylceramide beta-1,3-N-acetylgalactosaminyltransferase) | B3galnt1 B3galt3 B3gt3 | Q920V1 | 1 |
| UDP-glucose 6-dehydrogenase (UDP-Glc dehydrogenase) (UDP-GlcDH) (UDPGDH) (EC 1.1.1.22) | Ugdh | O70475 | 1 |
| UDP-N-acetylhexosamine pyrophosphorylase-like protein 1 (EC 2.7.7.-) | Uap1l1 | Q3TW96 | 1 |
| Ufm1-specific protease 1 (UfSP1) (EC 3.4.22.-) | Ufsp1 D5Ertd655e | Q9CZP0 | 1 |
| Ufm1-specific protease 2 (UfSP2) (EC 3.4.22.-) | Ufsp2 | Q99K23 | 1 |
| Uncharacterized aarF domain-containing protein kinase 4 | Adck4 | E9QLB8 | 1 |
| Uncharacterized aarF domain-containing protein kinase 5 (EC 2.7.11.-) | Adck5 | Q80V03 | 1 |
| Uncharacterized family 31 glucosidase KIAA1161 (EC 3.2.1.-) | Kiaa1161 | Q69ZQ1 | 1 |
| Uncharacterized membrane protein C19orf24 homolog | 0 | Q9DAZ5 | 1 |
| Uncharacterized methyltransferase WBSCR22 (EC 2.1.1.-) (Williams-Beuren syndrome chromosomal region 22 protein homolog) | Wbscr22 | Q9CY21 | 1 |
| Uncharacterized protein | 2610044O15Rik8 2610044O15Rik | Q8BG62 | 1 |
| Uncharacterized protein C10orf118 homolog (Oocyte-testis gene 1 protein) | Otg1 | Q8C9S4 | 1 |
| Uncharacterized protein C11orf74 homolog (Protein NWC) | Nwc | Q9CQI4 | 1 |
| Uncharacterized protein C11orf86 homolog | 0 | Q8VC23 | 1 |
| Uncharacterized protein C11orf95 homolog | 0 | Q4VA45 | 1 |
| Uncharacterized protein C12orf73 homolog | 0 | Q8BTC1 | 1 |
| Uncharacterized protein C14orf80 homolog | 0 | Q3UK37 | 1 |
| Uncharacterized protein C15orf39 homolog | 0 | Q3TEI4 | 1 |
| Uncharacterized protein C17orf62 homolog | 0 | Q3TYS2 | 1 |
| Uncharacterized protein C17orf89 homolog | 0 | A2AMZ4 | 1 |
| Uncharacterized protein C18orf25 homolog | 0 | Q8BH50 | 1 |
| Uncharacterized protein C19orf44 homolog | 0 | Q922C1 | 1 |
| Uncharacterized protein C1orf109 homolog | 0 | Q499E6 | 1 |
| Uncharacterized protein C1orf131 homolog | 0 | Q8CIL4 | 1 |
| Uncharacterized protein C1orf177 homolog | 0 | A2AVQ5 | 1 |
| Uncharacterized protein C1orf50 homolog | 0 | Q5EBG8 | 1 |
| Uncharacterized protein C20orf196 homolog | 0 | Q9D112 | 1 |
| Uncharacterized protein C20orf201 homolog | 0 | Q8BIG2 | 1 |
| Uncharacterized protein C21orf62 homolog | 0 | Q9D4G1 | 1 |
| Uncharacterized protein C4orf29 homolog | 0 | Q8C1A9 | 1 |
| Uncharacterized protein C5orf34 homolog | 0 | Q3UJC8 | 1 |
| Uncharacterized protein C5orf47 homolog | 0 | Q24JP4 | 1 |
| Uncharacterized protein C5orf52 homolog | 0 | Q9CR34 | 1 |
| Uncharacterized protein C6orf203 homolog | 0 | Q9CQF4 | 1 |
| Uncharacterized protein C7orf26 homolog | 0 | Q8BGA7 | 1 |
| Uncharacterized protein C7orf43 homolog | 0 | Q3UTZ3 | 1 |
| Uncharacterized protein C8orf76 homolog | 0 | Q9D2X8 | 1 |
| Uncharacterized protein C9orf135 homolog | 0 | Q9CQC3 | 1 |
| Uncharacterized protein CXorf57 homolog | 0 | Q8C779 | 1 |
| Uncharacterized protein KIAA0513 | Kiaa0513 | Q8R0A7 | 1 |
| Uncharacterized protein KIAA0753 | Kiaa0753 | Q6A000 | 1 |
| Uncharacterized protein KIAA0930 homolog | 0 | Q3UE31 | 1 |
| Uncharacterized protein KIAA1467 | Kiaa1467 | Q8BYI8 | 1 |
| Uncharacterized protein KIAA2013 | Kiaa2013 | Q91X21 | 1 |
| Unconventional myosin-Id | Myo1d | Q5SYD0 | 1 |
| Unconventional myosin-Ig | Myo1g | Q5SUA5 | 1 |
| Unconventional myosin-IXb | Myo9b | E9PWZ6 | 1 |
| Unconventional myosin-Va (Dilute myosin heavy chain, non-muscle) | Myo5a Dilute | Q99104 | 1 |
| Unconventional myosin-VI | Myo6 | E9Q3L1 | 1 |
| Unconventional myosin-X (Unconventional myosin-10) | Myo10 | F8VQB6 | 1 |
| Unconventional myosin-XIX (Myosin head domain-containing protein 1) | Myo19 Myohd1 | Q5SV80 | 1 |
| UPF0449 protein C19orf25 homolog | 0 | Q9D7E4 | 1 |
| UPF0462 protein C4orf33 homolog | D3Ertd751e | Q8BGN2 | 1 |
| UPF0472 protein C16orf72 homolog | 0 | Q14AM7 | 1 |
| UPF0488 protein C8orf33 homolog | 0 | Q3U6N9 | 1 |
| UPF0544 protein C5orf45 homolog | 0 | Q9D1F5 | 1 |
| UPF0552 protein C15orf38 homolog | 0 | Q9D0A3 | 1 |
| UPF0577 protein KIAA1324-like homolog (Estrogen-induced gene 121-like protein) (EIG121L) | 0 | Q3UZV7 | 1 |
| UPF0600 protein C5orf51 homolog | 0 | Q8BR90 | 1 |
| UPF0609 protein C4orf27 homolog | 0 | Q8CFE2 | 1 |
| UPF0686 protein C11orf1 homolog | 0 | Q9D131 | 1 |
| UPF0688 protein C1orf174 homolog | 0 | Q80WR5 | 1 |