Table 2 Exosome composition and roles of main components

Proteins

Tetraspanins

CD9, CD63, CD37, CD81, CD82, CD53

Exosome biogenesis, exosome cargo selection, targeting and uptake

[107, 187]

ESCRT machinery/MVB biogenesis

Alix, TSG-101

Exosome biogenesis

[49, 107]

Heat Shock Proteins (Hsp)

Hsp90, Hsc70, Hsp60, Hsp20, Hsp27

Exosomes release, signalling

[188,189,190]

Membrane transport and fusion

GTPases, Annexins, Flotillin, Rab GTPases, dynamin, syntaxin

Exosome secretion and uptake

[16, 66, 73, 140]

Major Histocompatibility Complex (MHC) molecules

MHC Class I, MHC Class II

Antigen presentation to generate immunological response

[191, 192]

Cytoskeletal proteins

Actin, Cofilin, Tubulin

Exosome biogenesis and secretion

[16, 19, 30]

Adhesion

Integrin-α,-β, P-selectin

Exosome targeting and uptake

[16, 19]

Glycoproteins

β-galactosidase, O-linked glycans, N-linked glycans

Exosomes targeting and uptake

[193, 194]

Growth factors and cytokine

TNF-α, TGF-β, TNF-related apoptosis inducing ligand (TRAIL)

Exosome targeting and uptake, signalling

[116, 162]

Other signalling receptors

Fas ligand (FasL), TNF receptor, Transferrin receptor (TfR)

Exosome targeting and signalling including apoptosis induction and iron transport

[16, 36, 116]

Lipids

Cholesterol

Exosome secretion

[195, 196]

Ceramides

Cargo sorting and exosome secretion

[54, 197]

Sphingomyelin

Exosome rigidity and signalling

[111, 197]

Phosphatidylserine

Exosome formation, signalling and uptake

[32, 196, 198]

Phosphatidylcholine

Exosome formation and structure

Phosphatidylethanolamine

Exosome formation and structure

Phosphatidylinositol

Exosome formation and structure

Gangliosides

Exosome rigidity