A list of 20 subfamilies of human RTKs along with their family members and respective extracellular and intracellular domains

Family nameMembersLigandsExtracellular domainIntracellular domainγ-secretase cleavageNuclear localization statusMechanism of nuclear localization
EGFRErbB1, ErbB2, ErbB3, ErbB4*EGF, transforming GF A (TGFA), heparin-binding EGF-like GF (HBEGF), betacellulin (BTC), Amphiregulin (AREG), epiregulin (EREG), epigen (EPGN)2-Cysteine rich domainsJM domain, tyrosine kinase domain, a C-terminal regulatory regionYesYesClathrin mediated endocytosis [35], retro-translocation by ER-associated trafficking machinery [36], nuclear localization signals (NLS) sequence [34]
InsRInsR*, IGF1R*, IRRINS-like GF-1 (IGF-1), IGF-2, INS2-Chains α and β, 2-leucine rich domain separated by a cysteine rich domain, 3-fibronectin type III (FNIII) domainsTyrosine kinase domainYesYesThe possible mechanism includes SUMOylation/via microtubules with the help of some proteins [p150Glued, AREG, importin-β, ran-binding protein 2 (RanBP2)] or clathrin mediated endocytosis [37], NLS
PDGFRPDGFRα, PDGFRβ, Kit, fibromyalgia syndrome-like tyrosine kinase 3 ligand (FLT3L), colony stimulating factor 1 (CSF1)*Platelet-derived GF (PDGF), PDGF-A, PDGF-AA, PDGF-AB, PDGF-AB/BB, PDGF-B, PDGF-BB, PDGF-C, PDGF-CC, PDGF-D, PDGF-DD5-Ig-like domainsJM domain, tyrosine kinase containing a long kinase insert domain region, a C-terminal extensionYesYesMediated by clathrin coated pits, β-importin, via TATA element modulatory factor 1 (TMF1) positive Golgi vesicles [38]
VEGFRVEGFR1*, VEGFR2*, VEGFR3*Vascular endothelial GF (VEGF)-A, VEGF-B, neuropilin-1, placental GF (PlGF), VEGF-C, VEGF-D7-Ig-like domainsJM domain, tyrosine kinase domainYesYesMediated by VEGF stimulation and complex formation with tissue transglutaminase II for endothelial cells [39], endocytosis [40]
FGFRFGFR1, FGFR2, FGFR3*, FGFR4*Fibroblast GF (FGF) 1–223-Ig-like domainsJM region, tyrosine kinase domainYesYesImportin-β-mediated interferons (INFS) mechanism [34] clathrin mediated endocytosis [41]
CCKCCK4/PTK7*Coreceptor for Wnt signaling7-Ig domainsCatalytic domain lacking tyrosine kinase activityYesYes-
NGFRTRKA*, TRKB*, TRKCNGF, BDNF, Neurotrophin 3 (NT3), NT43-Leucine repeats flanked by cysteine clusters and 2-Ig-like domainsTyrosine kinase domainYesYesMediated by Carrier vesicles [42], NLS, and phosphorylation dependent process [43], mediated by importins [44]
Hepatocyte GF receptor (HGFR)MET*, Recepteur d’ origine nantais (RON)Hepatocyte GF (HGF)Sema domain, a PSI domain, and 4-Ig-like plexins transcription factors (IPT) domainsJM domain, tyrosine kinase domain, carboxy-terminal tail regionYesYesMediated by Gab1 and importin-β, NLS [43], integral trafficking from ER to the nuclear envelop transport (INTERNET) [34]
Erythropoietin-producing human hepatocellular receptor (EPHR)EPHA1, EPHA2*, EPHA3, EPHA4*, EPHA5*, EPHA6, EPHA7*, EPHA8, EPHA10, EPHB1, EPHB2*, EPHB3*, EPHB4*, EPHB6*Ephrin A (1–5), ephrin B (1–3)Cysteine-rich domain and 2 FNIII repeatsTyrosine kinase domainYesYespH-Dependent nuclear localization signal [34]
AxlAxl*, Mer*, TYRO3*Growth arrest specific gene 6 (Gas 6)2-Ig-like domains and 2-FNIII domainsTyrosine kinase domainYesYesNLS [45]
TieTie*, TEKAngiopoietin (ANG) GFs (ANG1, ANG2, ANG4)2-Ig-like, 1-EGF, 3-FNIII domainsTyrosine kinase domainYesYesCaveolin mediated nuclear translocation [46]
RYKRYK*Wnt1, Wnt3aLeucine-rich domain with a WIF-type Wnt binding regionTyrosine kinase domain lacking kinase activityYesYesChaperone mediated, suppressor of Mek null 1/2 (smek1/2) functions as a chaperone and regulates nuclear translocation [47]
DDRDDR1, DDR2Collagen (I, IV, V, VI, VIII), collagen (I, III, X)Discoidin domain, discoidin-like domain, extracellular juxtamembrane regionJM domain, tyrosine kinase domain-YesStimulation with collagen leads to interaction with Sec61 translocon subunit beta (SEC61B) and results in nuclear translocation [48]
ROSROS-6-FNIII like domainsTyrosine kinase domain---
Leukocyte tyrosine kinase (LTK)LTK, ALKALK and LTK ligand 1 (ALKAL1), ALKAL22-Meprin A-5 protein and receptor protein phosphatase mu (2-MAM) domains 1-Ldla motif, cysteine rich and glycine rich domainsJM domain, tyrosine kinase domain---
RORROR1, ROR2Wnt5aIg-domain, cysteine-rich domains, and kringle-like domainsTyrosine kinase domain, proline-rich, serine-threonine rich domains-YesCleavage releasing mechanism in addition to Ran-GTPase pathway [45]
MUSKMUSK*Agrin3-Ig-like and 1-cysteine rich frizzled-like domainA JM domain, a kinase domain, and a short cytoplasmic tailYes--
LMRApoptosis associated tyrosine kinase (AATYK), AATYK, AATYK3A short extracellular domain containing leucine residuesTyrosine kinase domain---
RetRetGlial cell line-derived neurotrophic factor (GDNF), neuturin, artemin, persephin, growth differentiation factor-15 (GDF-15)4-Cadherin like domain, a cysteine rich domainJM domain, kinase domain, a C-terminal tail-Yes-
STYK1STYK1-It has a truncated extracellular domain, a single transmembrane domainA relatively short intracellular domain possessing tyrosine kinase activity---

The RTKs marked in asterisks (*) are reported to be cleaved by the γ-secretase enzyme [49, 50], and those in bold text are known to have nuclear localization. Noticeably, some of the RTKs undergo both γ-secretase cleavage and nuclear localization. -: no information is available as of now