Page 21 - 85 cell signalling pathways

Cell Signalling Biology Michael J. Berridge Module 2 Cell Signalling Pathways 2 21

Module 2: Table continued
Monomeric G protein, GEF or GAP Comments
Arf GEFs
Cytohesin 1
Cytohesin 4
GBF1 Golgi-specific brefeldin A resistant factor 1 functions in COPI-mediated protein transport
from the Golgi to the ER (Module 4: Figure COPI-coated vesicles)
ARNO/Geα2 Arf nucleotide-binding site opener (ARNO)
BRAG2 This Arf6 GEF binds to AMPA receptors to promote endocytosis
GTPase-activating proteins (GAPs)
Ras GAPs
p120RasGAP
Neurofibromin This tumour suppressor is lost in the inherited disorder neurofibromatosis type 1
SynGAP
GAP1m
GAP1IP 4 BP Ins1,3,4,5P 4 binds to this protein, causing it to dissociate from the plasma membrane
Ca 2 + -promoted Ras inactivator
CAPRI Ras GTPase-activating-like
RASAL
DAB2IP
Miro Mitochondrial Rho-GTPase functions in mitochondrial motility (Module 5: Figure
mitochondrial motility)
Rac GAPs
3BP-1 3BP-1 inactivates Rac.GTP by enhancing GTP hydrolysis (Module 2: Figure Rac signalling)
Rho GAPS
DLC1 (p122RhoGAP in mice) Deleted in liver cancer 1 is altered in many tumours. It regulates actin formation in
adhesion complexes (Module 6: Figure integrin signalling)
p190-RhoGAP Inhibits Rho activity during neutrophil chemotaxis (Module 11: Figure neutrophil
chemotactic signalling)
Oligophrenin-1 (OPHN1) Mutations in OPHN1 have been linked to mental retardation
Rab GAPs See Module 2: Figure Rab signalling
Rab3GAP
Rin1
Tbc1d1 These Rab GAPs function in the insertion of the GLUT4 transporter (Module7: Figure
Tbcd14/AS160 skeletal muscle E-C coupling)
Arf GAPS Function to inactivate Arf.GTP (Module 2: Figure Arf signalling)
Arf GAP1 group
ArfGAP1 Function in removing the coat from COPI-coated vesicles (Module 4: Figure COPI-coated
vesicles)
ArfGAP2
ArfGAP3
SMAP1 Stromal membrane-associated protein
SMAP2
Git1 G-protein-coupled receptor kinase interactors
Git2
AZAP group Arf GAP with ANK repeats and PH domain group of Arf GAPs
ACAP1 Arf GAP with coiled-coil, ANK repeats and PH domain (ACAP)
ASCP2
ASCP3
ASAP1 Arf GAP with Src homology 3, ANK repeats and PH domain (ASAP)
ASAP2
ASAP3
AGAP1 Arf GAP with GLD domain, ANK repeats and PH domain (AGAP)
AGAP2
AGAP3
ARAP1 Arf GAP with Rho GAP, ANK repeats and PH domain (ARAP)
ARAP2
ARAP3
Since some of the families are very large, only representative members have been included. Data for the large Rab family was based on
that from Supplementary Table S1 from Stenmark (2009).

activated by Cdc42·GTP, may play a role in actin forma- stabilize actin by phosphorylating LIM, which then phos-
tion during the growth of neurites. One of the downstream phorylates cofilin to prevent it from severing actin. Rho
targets of MRCK is the MYPT1 subunit (Module 5: Table also acts on diaphanous-related formin protein (Dia),
PP1 regulatory and inhibitory subunits and proteins)that which belongs to a formin-related protein family that in-
binds protein phosphatase 1δ (PP1δ) and which dephos- teracts with profilin to promote actin polymerization.
phorylates the myosin light chain (MLC). The other major function of ROK is to control contrac-
tion by activating myosin II in smooth muscle cells and
in non-muscle cells. The activity of myosin II is regulated
Rho kinase (ROK) by the phosphorylation status of the myosin light chain
Rho kinase (ROK) is a serine/threonine kinase that phos- (MLC) that is associated with the myosin head. When
phorylates key regulators of actin and myosin function MLC is dephosphorylated, myosin is inactive, but when
(Module 2: Figure Rho-regulated kinases). ROK acts to it is phosphorylated by the Ca 2 + -sensitive myosin light

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