Table 1.

The collagen family.

Collagen type	α Chains	Molecular species
Collagen I	α1(I), α2(I)	[α1(I)]2, α2(I) [α1(I)]3
Collagen II	α1(II)	[α1(II)]3
Collagen III	α1(III)	[α1(III)]3
Collagen IV	α1(IV), α2(IV), α3(IV), α4(IV), α5(IV), α6(IV)	[α1(IV)]2, α2(IV) α3(IV), α4(IV), α5(IV) [α5(IV)]2, α6(IV)
Collagen V	α1(V), α2(V), α3(V), α4(V)a	[α1(V)]2, α2(V) [α1(V)]3 [α1(V)]2α4(V) α1(XI)α1(V)α3(XI)
Collagen VI	α1(VI), α2(VI), α3(VI), α4(VI)b, α5(VI)c, α6(V)
Collagen VII	α1(VII)	[α1(VII)]3
Collagen VIII	α1(VIII)	[α1(VIII)]2, α2(VIII) α1(VIII), [α2(VIII)]2 [α1(VIII)]3 [α2(VIII)]3
Collagen IXe	α1(IX), α2(IX), α3(IX)	[α1(IX), α2(IX), α3(IX)]
Collagen X	α1(X)	[α1(X)]3
Collagen XI	α1(XI), α2(XI), α3(XI)d	α1(XI)α2(XI)α3(XI) α1(XI)α1(V)α3(XI)
Collagen XIIe	α1(XII)	[α1(XII)]3
Collagen XIII	α1(XIII)	[α1(XIII)]3
Collagen XIVe	α1(XIV)	[α1(XIV)]3
Collagen XV	α1(XV)	[α1(XV)]3
Collagen XVIe	α1(XVI)	[α1(XVI)]3
Collagen XVII	α1(XVII)	[α1(XVII)]3
Collagen XVIII	α1(XVIII)	[α1(XVIII)]3
Collagen XIXe	α1(XIX)	[α1(XIX)]3
Collagen XXe	α1(XX)	[α1(XX)]3
Collagen XXIe	α1(XXI)	[α1(XXI)]3
Collagen XXIIe	α1(XXII)	[α1(XXII)]3
Collagen XXIII	α1(XXIII)	[α1(XXIII)]3
Collagen XXIV	α1(XXIV)	[α1(XXIV)]3
Collagen XXV	α1(XXV)	[α1(XXV)]3
Collagen XXVI	α1(XXVI)	[α1(XXVI)]3
Collagen XXVII	α1(XXVII)	[α1(XXVII)]3
Collagen XXVIII	α1(XXVIII)	[α1(XXVIII)]3

Individual α chains, molecular species, and supramolecular assemblies of collagen types.

^aThe α4(V) chain is solely synthesized by Schwann cells.

^bThe α4(VI) chain does not exist in humans.

^cThe α5(VI) has been designated as α1(XXIX).

^dThe α3(XI) chain has the same sequence as the α1(II) chain but differs in its posttranslational processing and cross-linking.

^eFACIT, Fibril-Associated Collagens with Interrupted Triple helices.