Regulation of Blood–Testis Barrier (BTB) Dynamics during Spermatogenesis via the “Yin” and “Yang” Effects of Mammalian Target of Rapamycin Complex 1 (mTORC1) and mTORC2 - International Review of Cell and Molecular Biology - page 318

Growth factors/
mitogens

Insulin/IGF

Receptor of
Growth factors/
mitogens

Insulin
receptor

Amino acids

IRS

PI3K

Plasma
membrane

Energy
stress

Ras

Lkb1

PIP

PIP

P

P

PTEN

PDK1

Erk1/2

AMPK

P

P

P P

RSK

PKB

P

P

TSC2

P

P

TSC1

P

Rheb

P

P

P

Rictor

P

Sin1

mLST8
Deptor

Raptor
RPAS40

P

mTOR

Protor1/2

mLST8

mTOR Deptor

P

mTORC2

BAD

P

FoXOs

P P

mTORC1

P

SGK1

P P

P

PKC-

P

S6K

NDRG1

P

P P

rpS6 P

P

P

4E-BP1

MDM2

P GEF GDI

HDM2

SKAR

EF2K

eIF4B

P

P

eIF4E p53

GTPases

EF2

eIF4A

Proliferation and
survival

Actin cytoskeleton
reorganization

Protein synthesis

Keys:

Signaling shared
by mTORC1 and
mTORC2
Activating signaling of
mTORC1
Inhibitory signaling of
mTORC1

Activating signaling of
mTORC2
Inhibitory signaling of
mTORC2

mTOR upstream
signaling molecule
mTORC1 downstream
signaling molecule
mTORC2 downstream
signaling molecule

Phosphorylation

P

Figure 6.3 The likely mTOR signaling pathways involving mTORC1 and mTORC2 and
the corresponding interacting/regulatory proteins that regulate different cellular events
including BTB function in the testis via the effects on F-actin organization. By assembling
with different subunits, two mTOR complexes can be formed, namely, mTORC1 and