TIROSIN CHINASI CITOPLASMATICHE

SH3 SH2 KINASE DOMAINPH Tec (Btk/Itk/Bmx)

KINASE DOMAIN FAK/Pyk2

KINASE DOMAIN KINASE DOMAINSH2 Jak

Src (Blk, Lck, Lyn, Fyn, Fgr, Hck, Yes)

KINASE DOMAINSH2 SH2 ZAP70/Syk

(FERM) Focal adhesion targeting (paxillin binding)

TIROSIN CHINASI CITOPLASMATICHE

Abl/Arg

KINASE DOMAINSH3 SH2

KINASE DOMAINSH3 SH2

Ac. miristico/palmitico

Ac. miristico

G. Steven Martin : THE HUNTING OF THE SRC, Nature Reviews Molecular Cell Biology 2, 467-475 (2001)  

Src

Integrine

FAKYP397

SH2

SH3

Src

FAK e membri della famiglia del Src costituiscono un’unità di trasduzione del segnale da partedi molecole adesive definite INTEGRINE

FAK

SH2

SH3

SrcSH1

SH1

Outside-in signaling

FAK

Interazione con catena delle integrine e fattori di crescitaInterazione con fosfatidil inositolo (4,5) bisfosfato (PIP2)Interazione con proteine favorenti la polimerizzazione dell’actina (complesso Arp 2/3)

Interazione con paxillina

Cdominio cataliticodominio FERM dominio FATN

YP

AutofosforilazioneInterazioni con altre proteine(Src, PI3 chinasi, PLC

SH2YP

Sito di interazione con Grb2

SH2

Poli-P

Interazione con Cas

SH3

F1F1 F2F2 F3F3

Anche FAK come Src viene attivata in seguito alla rottura di interazioni intermolecolari chela mantengono in uno stato inibito.

Anche FAK come Src viene attivata in seguito alla rottura di interazioni intermolecolari chela mantengono in uno stato inibito.

FAKYP397

SH2

SH3

Src

PYPI3KAKT

PROLIFERAZIONE ESOPRAVVIVENZA

Il distacco da proteine della matrice extracellulare induce una forma di apoptosi (chiamata “anoikis”)che determina il fenomeno della cosiddetta “crescita dipendente dall’ancoraggio”

FAKYP397

SH2

SH3

SH1

Src

YP925

Grb2 Poli-P

Sos

Ras

RafMAPK

MAPK (ERK1/2)

TRASCRIZIONE GENICAProliferazione e sopravvivenza cellulare

CasPYPY

PYCrkPoli-P

Dock180

Rac

PAK

JNKPolimerizzazione dell ’actinae protrusione del lamellopodio

Movimento cellulare

PI3-chinasi

P P P PPP

Fosfatidilinositolo 3,4,5 fosfato

PH

GEFs

Rac, Cdc42

PIP5-chinasi

Fosfatidilinositolo 4,5 fosfato

P PP

P

PLCIP3

paxillina

Interazione con altreProteine cito-scheletriche e segna-lanti

FAK, Src e altre chinasi vengono inibite da tirosin fosfatasi che sono sensibili all’azione inibitoria di ROIs

Protein fosfatasiattiva

Protein fosfatasiinattiva

FAK, Src, GF-Rs, MAP chinasi (JNK, ERKs)

attive

FAK, Src, GF-Rs, MAP chinasi (JNK, ERKs)

inattive

La transizione epitelio-mesenchimale rappresenta una modificazione tipica dei tumori epitelialimetastatici

An epithelial-mesenchymal transition (EMT) is a biologic process that allows a polarized epithelial cell, which normally interacts with basement membrane via its basal surface, to undergo multiple biochemical changes that enable it to assume a mesenchymal cell phenotype, which includes enhanced migratory capacity, invasiveness, elevated resistance to apoptosis, and greatly increased production of ECM components . The completion of an EMT is signaled by the degradation of underlying basement membrane and the formation of a mesenchymal cell that can migrate away from the epithelial layer in which it originated. (Kalluri and Weinberg, J. Clin. Invest. 119:1420, 2009)

EPITHELIAL-MESENCHIMAL TRANSITION

MESENCHIMAL-EPITHELIAL TRANSITION

giunzioni serrate (tight junction)

giunzioni aderenti (adherens junctions)

E-caderina

cat.

p120 cat.

F-actina

F-actinavinculina

p120 cat.

microtubuli

cat.

Rac

Rho

Movimento

Previene endocitosi e de-gradazione E- caderina

Migrazione nel nucleo e trascrizione geni implicati nella proliferazione cellulare

E-caderina

giunzioni serrate (tight junction)

giunzioni aderenti (adherens junctions)

cat.

cat.

p120 cat.

F-actina

F-actinavinculinaE-caderina

Recettori per fattori di crescita:TGFRI e II, IGF-1R, EGFR, c-Met

L’aumentata stimolazione con fattori di crescita altera funzioni di E-caderineIn diversi modi

L’aumentata stimolazione con fattori di crescita altera funzioni di E-caderineIn diversi modi

1. Il promotore del gene per le E-caderine viene represso da repressori trascrizionali (Snail, Twist, Slug e altri) indotti da Recettori per GF e altre vie attivate nel corso di “progressione” tumorale (compreso Nf-B).

2. Tirosin chinasi recettoriali (EGFR, IGF-1R, c-Met, FGF) e non recettoriali (c-Src) inducono fosforilazione e successiva ubiquitinilazione di E-caderine e catenina con conseguente degradazione nel proteosoma. La fosforilazione di E-caderina comporta anche il distacco di e catenine.

3. Proteasi (metallo-proteasi – MMP) proteolizzano E-caderine alterando contatti cellula-cellula.

4. Gli stessi segnali che “down-regolano” espressione di E-caderine aumentano espressione di N-caderine (il cosiddetto “caderin-switch”), che sono espresse da cellule mesenchimali e regolano positivamente il movimento cellulare.

cat. cat.

p120 cat.

F-actina

vinculina

E-caderina

Rac Cdc42 Rho

movimentoSress fibers, focal adhesion

E-caderina

cat.PP P

DEGRADAZIONE

NUCLEO

Trascrizione geni implicati in proliferazione e progressione

GSK-3

SnailP

P

cat.

Repressione sintesi E-caderine

Inibizione di GSK da parte di GF-Rs o altri stimoli favorisce la progressione neoplastica

Un meccanismo aggiuntivo di regolazione della funzione di catenica è rappresentato da un suo aumento diespressione in cellule stimolate con proteine wnt (ampia famiglia di fattori di crescita poco caratterizzati)

Gene onco-soppressore, la cuimutazione in cellule della linea germinale determina laPoliposi Adenomatosa Famigliaredel Colon

a | In the absence of WNT signalling, -catenin levels in the cytoplasm and nucleus are low as a result of continuous phosphorylation by the serine/threonine kinases CK1 (casein kinase 1) and GSK3 (glycogen synthase kinase 3), leading to binding of -transducin-repeat-containing protein (TRCP) and to ubiquitylation and degradation by the proteasome. The destruction complex is composed of CK1 and GSK3, as well as the anchor proteins AXIN1 (axis inhibition protein 1 ) and APC (adenomatous polyposis coli). In the nucleus, TCF (T-cell factor) molecules are bound by co-repressors such as GRG/TLE (Groucho/transducin-like enhancer) proteins that shut off expression of WNT target genes. Other components of the repressor complex include CTbP (C-terminal binding protein) and HDACs (histone deacetylases). -catenin in the nucleus is inhibited from binding TCF by ICAT (cell autonomous inhibitor of -catenin and TCF) . The Frizzled receptor complex — composed of Frizzled and LRP5 (LDL-receptor-related protein 5) or LRP6 — can also be actively inhibited by receptor-bound soluble inhibitors such as DKK1 (Dickkopf homologue 1). b | Upon binding of a lipid-modified WNT protein to the receptor complex, a signalling cascade is initiated. LRP is phosphorylated by CK1 and GSK3, and AXIN1 is recruited to the plasma membrane. The kinases in the -catenin destruction complex are inactivated and -catenin translocates to the nucleus to form an active transcription factor complex with TCF, leading to transcription of a large set of target genes. In the nucleus, -catenin binds to TCF and LEF factors and recruits co-factors such as legless (LGS; also known as BCL9) and Pygopus (PYGO), CBP/p300, Brahma and MED12 to initiate transcription99, 100, 101. DVL, mammalian homologue of Drosophila Dishevelled; PP2A, protein phosphatase 2A.

WNT PROTEINS POSSONO ANCHE ATTIVARE RHO GTPASI E SEGNALI CALCIOWNT PROTEINS POSSONO ANCHE ATTIVARE RHO GTPASI E SEGNALI CALCIO

a | Planar cell polarity (PCP) signalling does not involve -catenin, LRP (LDL-receptor-related protein) or TCF (T-cell factor) molecules, but leads to the activation of the small GTPases RHOA (RAS homologue gene-family member A) and RAC1, which activate the stress kinase JNK (Jun N-terminal kinase) and ROCK (RHO-associated coiled-coil-containing protein kinase 1) and leads to remodelling of the cytoskeleton and changes in cell adhesion and motility. Through largely unknown mechanisms, canonical -catenin signalling can be inhibited by the PCP pathway. b | WNT–Ca2+ signalling is mediated through G proteins and phospholipases and leads to transient increases in cytoplasmic free calcium that subsequently activate the kinases PKC (protein kinase C) and CAMKII (calcium calmodulin mediated kinase II) and the phosphatase calcineurin. The activation of PLC (phospholipase C) by DVL (mammalian homologue of Drosophila Dishevelled) leads to the cleavage of PtdIns(4,5)P2 (phosphatidylinositol-4,5-bisphosphate) into InsP3 (inositol trisphosphate) and DAG (diacylglycerol). DAG, together with calcium, activates PKC, whereas InsP3 binding to receptors on the membranes of intracellular calcium stores leads to a transient increase in cytoplasmic free calcium, often also triggering an increase from extracellular stores. AP1, activator protein 1; CDC42, cell-division cycle 42; DAAM, Dishevelled-associated activator of morphogenesis; NFAT, nuclear factor of activated T cells; PDE6, phosphodiesterase 6.

Dipartimento di PatologiaSezione di Patologia Generale

Università di Verona

R. Ren, 5:172-183

Haematopoietic stem cell

Common myeloid progenitors

Chronic myeloid leukemia-chronic phase

Granulocyte/macrophage progenitors

Megakaryocyte/erythrocyte progenitors

Common lymphoid progenitorsChronic myeloid leukemia-blast phase (70%)

Chronic myeloid leukemia-blast phase(30%)

With the aid of several mediator proteins, BCR-ABL associates with Ras and stimulates its activation. The adaptor protein, growth factor receptor-bound protein 2 (GRB2), interacts with BCR-ABL through the proximal SRC homology 2 (SH2)-binding site that develops when the tyrosine 177 (Y177) residue of BCR-ABL is autophosphorylated. GRB2, when bound to BCR-ABL, interacts with the son of sevenless (SOS) protein. The resulting BCR–ABL–GRB2–SOS protein complex activates Ras. The adaptor proteins CRKL (CRK-like) and SHC (SH2-containing protein) can also mediate the BCR-ABL activation of Ras. Ras and the mitogen activated protein kinase (MAPK) pathway are coupled by Raf (a serine/threonine kinase). Raf catalyses the phosphorylation of the mitogen-activated and extracellular-signal regulated kinase kinases 1 and 2 (MEK1 and MEK2); this results in their activation. Through the stimulation of the Ras–Raf pathway, BCR-ABL increases growth factor-independent cell growth. BCR-ABL also associates with and activates the phosphatidylinositol-3 kinase (PI3K) pathway, suppressing programmed cell death and increasing cell survival. BCR-ABL is associated with components of the focal adhesion(that is, actin, paxillin and focal adhesion kinase, or FAK); the activation of CRKL–FAK–PYK2 leads to a decrease in cell adhesion. BCR-ABL also associates with the Janus kinase and signal transducer and activator of transcription (JAK–STAT) pathway. Finally, BCR-ABL activates pathways that lead to atypical responses to chemotactic factors, which leads to an increase in cell migration. BCR-ABL also associates with survival proteins that interact with the mitochondrial-based BCL2 family. CAS, p130 CRK-associated substrate; GAB2, GRB2-associated binding protein 2; SHIP, SH2-containing inositol-5-phosphatase

Weisberg et al. 7:345, 2007

(Imatinib mesilato)

Figure 1.6

Copyright © 2011 Academic Press Inc.

Figure 3.1

Copyright © 2011 Academic Press Inc.

Esempi di difese locali

Figure 1.2

Copyright © 2011 Academic Press Inc.

Figure 1.3

Copyright © 2011 Academic Press Inc.

Pattern recognition receptors

Pathogen associated molecular pattern

DAMP: Damage associated molecular pattern

NECROSI

Figure 1.4

Copyright © 2011 Academic Press Inc.

ITAM (Immunoreceptor tyrosine-based inhibitory motif) : DExxYxxL/I(x)6-7YxxL/I

TRASDUZIONE DEL SEGNALE DA PARTE DI RECETTORI IMMUNI

ITAM ITIM: I/VxxYxxL/V

FcRIIA FcRIIB

Immunoreceptor tyrosine-based inhibitory motif

TRASDUZIONE DEL SEGNALE DA PARTE DI RECETTORI IMMUNI

attivazione

C-type lectins

ZAP70

Fyn/ LckSyk

Syk

SykSyk

Lyn

Lyn

Lyn/Hck/Fgr

Abl

Lipide fosfatasi

Protein fosfatasi

YPSYK

SFK

?

SYKYP

ITA

M

ANCHE ALCUNE FAMIGLIE DI INTEGRINE (2 E 3) TRASDUCONO IL SEGNALEMEDIANTE UN MODULO BASATO SU ADATTATORI CON SEQUENZA ITAM E SYK