Figure 1: Androgen actions via intracellular androgen receptor.
(1) In the classical pathway. (2) Bound with the SH3 domain. (3) Bound to SHBG. Abbreviations: T, testosterone; DHT, dihydrotestosterone; 5αR, 5alpha reductase enzyme; AR, androgen receptor; PKA, protein kinase A; GP, G-protein; SH2, Src homology domain 2; SH3, Src homology domain 3; PTK, protein tyrosine kinase; MAPK, mitogen-activated protein kinase; SHBGR, steroid hormone-binding globulin receptor; cAMP, cyclic adenosine monophosphate.
Androgen actions via intracellular androgen receptor mediated pathways. Testosterone (T)
can be converted to dihydrotestosterone (DHT) by the 5αR enzyme. 1) In the classical
pathway, androgen freely passes through the membrane bi-layer and binds cytoplasmic
androgen receptor (AR). Bound AR translocates to the nucleus, binds to a DNA response
element on a promoter of an androgen responsive gene and stimulates transcription. 2)
Bound AR interacts with the SH3 domain of the tyrosine kinase c-Src to activate the MAPK
pathway and influence AR-mediated transcription via phosphorylation of coactivator/
receptor complexes. 3) Androgen bound to steroid hormone binding globulin (SHBG) can
activate SHBG receptor (SHBGR) and lead to an increase in PKA activity. PKA may
influence AR-mediated transcription via alteration of phosphorylation status of AR and AR
coregulators. Abbreviations: T = testosterone, DHT = dihydrotestosterone, 5αR = 5 alpha
reductase enzyme, AR = androgen receptor, PKA = protein kinase A, GP = g-protein, SH2 =
Src homology domain 2, SH3 = Src homology domain 3, PTK = protein tyrosine kinase,
MAPK = mitogen-activated protein kinase, SHBGR = steroid hormone binding globulin
receptor, cAMP = cyclic adenosine monophosphate.
The source is not mentioned here.
The figures are not 100% identical, but clearly not independent either.