Table 1. Directly associated tetraspanin partner proteins^*.

Tetraspanin	Partner protein	Function	Refs
CD9	CD9	CD9–CD9 dimer may be a basic structural unit	37
	EWI-2 (IGSF8, CD316)	Modulates integrin-dependent cell motility and/or spreading	13,81,139, 177
	EWI-F (C9P-1, FPRP)	Functions unknown	178,179
	Claudin-1	CD9 stabilizes expression of non-junctional Claudin-1	14
	HB-EGF	CD9 upregulates both diphtheria toxin binding and mitogenic functions of HB-EGF	128,167
CD81	CD81	CD81–CD81 dimer may be a basic structural unit	7,37,177
	EWI-2	Modulates integrin-dependent cell motility and/or spreading; also, CD81 supports maturation and surface expression of EWI-2	13,81,139, 177,180
	EWI-2wint	Inhibits hepatitis C virus interaction with CD81	166
	EWI-F	Functions unknown	178,179
	CD19	CD81 supports maturation and surface expression of CD19	89,181
	α4β1 Integrin	CD81 supports α4β1 integrin adhesion strengthening	90,138
CD151	CD151	CD151–CD151 dimer may be a basic structural unit	37
	α3β1 Integrin	CD151 affects integrin-dependent adhesion and motility	53,137,138, 147,182
	α6β1 Integrin	CD151 affects integrin-dependent adhesion strengthening	176
	α6β4 Integrin	CD151 affects integrin- dependent adhesion and motility	45,53,147, 172,173
	α7β1 Integrin	Functions not yet demonstrated	172
CD63	Syntenin-1	Endocytosis regulation	157

^*This table does not include tetraspanins specialized to function in the eye (Peripherin, ROM1) or urothelial membrane (uroplakin 1a, uroplakin 1b).

EWI-2wint, EWI-2 without its N-terminal immunoglobulin domain¹⁶⁶; HB-EGF, heparin-binding epidermal growth factor-like growth factor.