Table 1.
Major ECM components and their key domains, post-translational modifications and tissue distributions
| Molecule name | Gene name(s)* | Domains† | Post-translational modification(s)†,‡ | Examples of tissue distribution† |
|---|---|---|---|---|
| Fibril-forming collagens | ||||
| Collagen I | COL1A1, COL1A2 | Fibrillar collagen NC1; VWFC | Glyco; Hyl; Hyp; pro; X | Bone, cornea, skin, tendon |
| Collagen II | COL2A1 | Fibrillar collagen NC1; VWFC | Glyco; Hyl; Hyp; X | Cartilage, vitreous body |
| Collagen III | COL3A1 | Fibrillar collagen NC1; VWFC | Glyco; Hyl; Hyp; phospho; S–S; X | Blood vessels, bone, skin |
| Collagen V | COL5A1–COL5A3 | Collagen-like; fibrillar collagen NC1; laminin G-like/TSP N-terminal; VWFC | Glyco; Hyl; Hyp; phospho; sulf; S–S; X | Blood vessels, bone, cornea, placenta, skin, tendon |
| Collagen XI | COL11A1, COL11A2 | Collagen-like; fibrillar collagen NC1; laminin G-like/TSP N-terminal | Glyco; Hyp; pro; S–S; X | Cartilage, placenta, tendon |
| Collagen XXIV | COL24A1 | Collagen-like; fibrillar collagen NC1; laminin G-like/TSP N-terminal | Glyco | Bone, cornea |
| Collagen XXVII | COL27A1 | Collagen-like; fibrillar collagen NC1; laminin G-like/TSP N-terminal | Glyco; phospho | Cartilage |
| Network-forming collagens | ||||
| Collagen IV | COL4A1–COL4A6 | Collagen IV NC1 | Glyco; Hyl; Hyp; phospho; pro; S–S; Ubl; X | Basement membranes |
| Collagen VIII | COL8A1, COL8A2 | C1q | Hyp; pro | Basement membranes, blood vessels, connective tissues |
| Collagen X | COL10A1 | C1q | Hyp | Calcifying cartilage |
| Beaded filament–forming collagens | ||||
| Collagen VI | COL6A1–COL6A3, COL6A5, COL6A6 | BPTI/Kunitz inhibitor; collagen-like; FNIII; VWFA | Glyco; Hyl; Hyp; phospho; S–S | Bone, cartilage, cornea, skin |
| Collagen XXVI | EMID2 | Collagen-like; EMI | Glyco; Hyp; S–S | Ovary, testis |
| Collagen XXVIII | COL28A1 | BPTI/Kunitz inhibitor; collagen-like; VWFA | S–S | Basement membranes |
| Anchoring fibrils | ||||
| Collagen VII | COL7A1 | BPTI/Kunitz inhibitor; collagen-like; FNIII; VWFA | Glyco; Hyl; Hyp; S–S | Anchoring fibrils, basement membranes |
| Fibril-associated collagens with interrupted triple helices | ||||
| Collagen IX | COL9A1–COL9A3 | Collagen-like; laminin G-like/TSP N-terminal | Glyco; Hyp; S–S; X | Cartilage, vitreous body |
| Collagen XII | COL12A1 | Collagen-like; FNIII; laminin G-like/TSP N-terminal; VWFA | Glyco; Hyp; S–S | Connective tissues |
| Collagen XIV | COL14A1 | Collagen-like; FNIII; laminin G-like/TSP N-terminal; VWFA | Glyco; Hyl; Hyp; S–S | Connective tissues |
| Collagen XVI | COL16A1 | Collagen-like; laminin G-like/TSP N-terminal | Glyco; Hyp; S–S | Cartilage, papillary dermis, placenta |
| Collagen XIX | COL19A1 | Collagen-like; laminin G-like/TSP N-terminal | Hyp; S–S | Basement membranes |
| Collagen XX | COL20A1 | Collagen-like; FNIII; laminin G-like/TSP N-terminal; VWFA | Glyco | Widespread |
| Collagen XXI | COL21A1 | Collagen-like; laminin G-like/TSP N-terminal; VWFA | Glyco | Widespread |
| Collagen XXII | COL22A1 | Collagen-like; laminin G-like/TSP N-terminal; VWFA | Glyco | Tissue junctions |
| Transmembrane collagens and collagen-like proteins | ||||
| Collagen XIII | COL13A1 | Collagen-like; helical TM | S–S | Cell junctions |
| Collagen XVII | COL17A1 | Collagen-like; helical TM | Glyco; Hyp; phospho; pro; S–S | Hemidesmosomes |
| Collagen XXIII | COL23A1 | Collagen-like; helical TM | Pro | Brain, cornea, kidney, lung, skin, tendon |
| Collagen XXV | COL25A1 | Collagen-like; helical TM | Glyco; Hyl; Hyp; pro | Brain |
| Ectodysplasin A | EDA | Collagen-like; helical TM | Glyco; pro | Hair follicles, keratinocytes, sweat glands |
| EMID1 | EMID1 | Collagen-like; EMI | Glyco; S–S | |
| Gliomedin | GLDN | Collagen-like; helical TM; olfactomedin-like | Glyco; pro | Brain, placenta, sciatic nerve, spinal cord |
| MARCO | MARCO | Collagen-like; helical TM; SRCR | Glyco; S–S | Macrophages |
| MSR1 | MSR1 | Collagen-like; helical TM; SRCR | Glyco; phospho; S–S | Macrophages |
| PSPs | SFTPA1, SFTPA2, SFTPD | C-type lectin; collagen-like | Acetylation; glyco; Hyl; Hyp; S–S | Lung |
| Multiplexin collagens | ||||
| Collagen XV | COL15A1 | Collagen-like; laminin G-like/TSP N-terminal | Glyco; Hyp; S–S | Basement membranes |
| Collagen XVIII | COL18A1 | Frizzled; laminin G-like/TSP N-terminal | Glyco; Hyp; pro; S–S | Basement membranes |
| Elastin and microfibrillar proteins | ||||
| Elastin | ELN | Hyp; S–S; X | Elastic fibres | |
| Emilins | EMILIN1–EMILIN3 | C1q; collagen-like; EMI | Glyco; phospho; S–S | Elastic fibres |
| Fibrillins | FBN1–FBN3 | EGF-like; TGF-BP | Glyco; phospho; pro; S–S; X | Microfibrils |
| Fibulins | EFEMP1, EFEMP2, FBLN1, FBLN2, FBLN5, FBLN7, HMCN1 | Anaphylatoxin-like; EGF-like; Ig-like C2-type; nidogen G2 β-barrel; sushi; TSP type 1; VWFA | Glyco; phospho; S–S | Basement membranes, connective tissues, retina (EFEMP1), teeth (FBLN7) |
| MAGPs | MFAP1, MFAP2, MFAP4, MFAP5 | Fibrinogen C-terminal; SXC | Acetylation; glyco; phospho; S–S; sulf; X | Microfibrils |
| Non-collagenous glycoproteins | ||||
| Fibronectin | FN1 | FNI; FNII; FNIII | Glyco; phospho; pro; S–S; sulf; X | Widespread |
| Laminins | LAMA1–LAMA5, LAMB1–LAMB4, LAMC1–LAMC3 | Laminin EGF-like; laminin G-like/TSP N-terminal; laminin IV type A; laminin N-terminal | Glyco; phospho; pro; S–S | Basement membranes |
| Nidogens | NID1, NID2 | EGF-like; NIDO; nidogen G2 β-barrel; thyroglobulin type 1 | Glyco; S–S; sulf | Basement membranes |
| SPARC | SPARC | EF-hand; follistatin-like; Kazal-like | Glyco; S–S | Basement membranes |
| Tenascins | TNC, TNN (tenascin-W), TNR, TNXB | EGF-like; fibronectin C-terminal; FNIII | Glyco; phospho; S–S | Nervous system, skeletal tissues, vasculature |
| Thrombospodins | COMP, THBS1–THBS4 | COMP N-terminal (COMP); EGF-like; laminin G-like/TSP N-terminal; TSP C-terminal; TSP type 1; TSP type 3; VWFC | Glyco; phospho; S–S | Cartilage (COMP), widespread |
| Matrilins | ||||
| Matrilins | MATN1–MATN4 | EGF-like; VWFA | Glyco; phospho; S–S | Cartilage (MATN1, MATN3), connective tissues (MATN2, MATN4) |
| Basement membrane proteoglycans | ||||
| Agrin | AGRN | EGF-like; Kazal-like; laminin EGF-like; laminin G-like; NtA; SEA | Glyco; S–S | Basement membranes |
| Bamacan | SMC3 | Acetylation; glyco; phospho | Basement membranes | |
| Perlecan | HSPG2 | EGF-like; Ig-like C2-type; laminin EGF-like; laminin G-like; laminin IV type A; LDL-receptor class A; SEA | Glyco; pro; S–S | Basement membranes |
| Hyalectans (lecticans) | ||||
| Aggrecan | ACAN | C-type lectin; EGF-like; Ig-like V-type; link; sushi | Glyco; pro; S–S | Cartilage |
| Brevican | BCAN | C-type lectin; EGF-like; Ig-like V-type; link; sushi | Glyco; S–S | Nervous system |
| Neurocan | NCAN | C-type lectin; EGF-like; Ig-like V-type; link; sushi | Glyco; S–S | Nervous system |
| Versican | VCAN | C-type lectin; EGF-like; Ig-like V-type; link; sushi | Glyco; phospho; S–S | Widespread |
| Small leucine-rich proteoglycans | ||||
| Asporin | ASPN | LRRNT | Glyco; S–S | Cartilage |
| Biglycan | BGN | Glyco; pro; S–S | Connective tissues | |
| Chondroadherin | CHAD | LRRNT | Glyco; S–S | Chondrocytes |
| Decorin | DCN | Glyco; pro; S–S | Connective tissues | |
| Epiphycan | EPYC | LRRNT | Glyco; S–S | Cartilage, ligament, placenta |
| Fibromodulin | FMOD | LRRNT | Glyco; S–S; sulf | Connective tissues |
| Keratocan | KERA | LRRNT | Glyco; S–S | Cornea, trachea |
| Lumican | LUM | LRRNT | Glyco; S–S; sulf | Cartilage, cornea |
| Mimecan | OGN | Glyco; S–S | Bone, cornea | |
| Nyctalopin§ | NYX | LRRNT | Glyco; S–S | Kidney, retina |
| Opticin§ | OPTC | LRRNT | Glyco; S–S; sulf | Brain, cartilage, iris, retina |
| Osteomodulin | OMD | LRRNT | Glyco; S–S; sulf | Bone |
| Podocan§ | PODN | LRRNT | Glyco | Heart, kidney, liver, pancreas, smooth muscle |
| Podocan-like protein–1§ | PODNL1 | LRRNT | Glyco | Bone |
| Prolargin | PRELP | Glyco; S–S | Basement membranes, connective tissues | |
| Tsukushin§ | TSKU | LRRNT | Glyco | Brain, iris |
| Testicans | ||||
| Testicans | SPOCK1–SPOCK3 | Kazal-like; thyroglobulin type 1 | Glyco; phospho; S–S | Cornea, nervous system |
BPTI, bovine pancreatic trypsin inhibitor; COMP, cartilage oligomeric matrix protein; ECM, extracellular matrix; EGF, epidermal growth factor; EMI, EMILIN domain; EMID, EMI domain–containing protein; FNI, fibronectin, type I; FNII, fibronectin, type II; FNIII, fibronectin, type III; G-like, globular-like; Ig, immunoglobulin; LDL, low-density lipoprotein; LRRNT, leucine-rich repeat N-terminal domain; MAGP, microfibril-associated glycoprotein; MARCO, macrophage receptor with collagenous structure; MSR1, macrophage scavenger receptor types I and II; NC1, non-collagenous-1; NtA, N-terminal agrin; PSP, pulmonary surfactant-associated protein; SEA, sea urchin sperm protein, enterokinase, agrin; SPARC, secreted protein, acidic and rich in cysteine; SRCR, scavenger receptor cysteine-rich; SXC, six-cysteine; TGF-BP, transforming growth factor–β–binding protein-like; TM, transmembrane; TSP, thrombospondin; VWFA, von Willebrand factor, type A; VWFC, von Willebrand factor, type C.
*
Human gene names are listed.
†
Data were extracted from the UniProt Knowledgebase (http://uniprot.org) (release 2012_07) (UniProt Consortium 2012).
‡
Modifications (including inferred): glyco, glycosylation; Hyl, lysine hydroxylation; Hyp, proline hydroxylation; phospho, phosphorylation; pro, proteolytic processing; S–S, disulphide bonding; sulph, sulphation; Ubl, ubiquitin-like conjugation; X, covalent crosslinking.
§
Small leucine-rich proteoglycan family member that is not considered a proteoglycan due to lack of glycosaminoglycan chains.