Table 1. Receptors as co-ordinators of complex formation, and function in genetic and epigenetic changes in gene activation.

In IFNγ, EGF, FGF and SR systems, similarities in terms of the steps involved in specific gene activation are indicated. References are provided, and detailed references for the other molecules involved are indicated in the text. ERK, extracellular-signal-regulated kinase; Msk1, mitogen- and stress-activated kinase 1; Rsk1, ribosomal S6 kinase 1; Src, cytoplasmic tyrosine kinase.

Component	Signalling systems
	IFNγ	EGF	FGF	SR
Ligand	IFNγ: (i) activates receptor; (ii) provides NLS [31,32]	EGF, TGFα: (i) activate receptor	FGF: (i) activates receptor; (ii) provides NLS	SH: (i) activates receptor
Receptor	IFNGR1: (i) transcription factor/co-transcription factor [40]	EGFR: (i) transcription factor/co-transcription factor; (ii) provides NLS; (iii) RTK and other kinase activity for epigenetic modification	FGFR1, FGFR2: (i) transcription factor/co-transcription factor; (ii) RTK activity for epigenetic modification	SR: (i) transcription factor/co-transcription factor; (ii) platform for co-activators
JAKs	IFNGR2: (i) moves JAK2 to IFNGR1 [39] (i) STAT activation; (ii) epigenetic modification [41]	(i) STAT activation; (ii) epigenetic modification	(i) STAT activation; (ii) epigenetic modification
STATs	STAT1α: (i) transcription factor in activated state [41]; (ii) heterochromatin stabilizer in non-phosphorylated state [41]	STATs 1, 3, 5: (i) transcription factors	STAT5: (i) transcription factors	STAT5: (i) transcription factor for progesterone receptor [70]
Other associated nuclear kinases and co-factors	MAPK ERK1/2 NF-κB [12]	MAPK Src [69]	MAPK Rsk1 [70]	MAPK SRC 1, 2, 3 [71] Msk1 and ERK [71]