Biochemistry
Cell Signaling Pathways Growth Factors
Compiled By Simon Mwangi
Edition: 2024/25
, Science | Biochemistry I of VI pages
1. what are growth factors?
substances capable of inducing cell growth, proliferation, healing, and/or differentiation
2. what are the major types of growth factors? (2)
proteins and steroids
3. signaling of growth factors involves
binding to a cell membrane receptor and then activation of various intracellular signaling pathways
4. what are the major families of growth factor receptors? (3)
tyrosine kinase activity seine/threonine kinase activityG protein coupled receptor
5. nerve growth factor (NGF) signaling pathway
Binding interaction between NGF and the TrkA receptor facilitates receptor dimerization and tyrosine residue
of the cytoplasmic tail by adjacent Trk receptors. Trk receptor phosphorylation sites operate as Shc adaptor
docking sites, which undergo phosphorylation by the TrkA receptor. The Trk receptor complex recruits a
adaptor protein called growth factor-receptor bound protein-2 (Grb2) along with a docking protein called
Binder-1 (GAB1) (not shown). Subsequently, phosphatidylinositol-3 kinase (PI3K) is activated, resulting in
6. TrkA
tropomyosin receptor kinase A
7. TrkA is a high affinity receptor involved in
neuronal differentiation and preventing cell death
survival genes
8. p75
neurotrophin receptor
9. p75 is raining expressed in early
neuronal development
promote apoptosis
10. EGF signaling pathway
Signaling pathways and inhibitors of EGFR. Activation of EGFR leads to
phosphorylation of specific tyrosine residues, and recruitment of several proteins at the intracellular portion of
receptors. Phospholipase C (pink) and STAT transcription factors (blue) bind directly to the receptor, whereas
pathway (orange) and PI3K pathway (green) need several specific adaptor molecules (yellow). PI3K can also
directly any of the erbB partners of EGFR heterodimers. Concomitantly, the activated receptors undergo
and follow two possible routes: lysosomal degradation or importin-mediated nuclear translocation. Once in the
EGFR can either behave as a proper transcription factor (for cyclin D1 up-regulation) or as coregulator of
gene transactivators. Both pathways result in nuclear activation of genes related with cell proliferation,
invasion, and metastasis. Two main strategies are available for EGFR kinase inhibition: mAb and
TKIs. mAbs act extracellularly, avoiding EGFR ligands binding, whereas TKIs compete with the ATP binding
the kinase domain of the receptor. DAG, 1,2-diacylglycerol; IP3, inositol 1,3,5-triphosphate; PLC,
C; Erk-1, extracellular signal-regulated kinase-1; Erk-2, extracellular signal-regulated kinase-2; FAK, focal
Biochemistry 2024/25 Edition
Cell Signaling Pathways Growth Factors
Compiled By Simon Mwangi
Edition: 2024/25
, Science | Biochemistry I of VI pages
1. what are growth factors?
substances capable of inducing cell growth, proliferation, healing, and/or differentiation
2. what are the major types of growth factors? (2)
proteins and steroids
3. signaling of growth factors involves
binding to a cell membrane receptor and then activation of various intracellular signaling pathways
4. what are the major families of growth factor receptors? (3)
tyrosine kinase activity seine/threonine kinase activityG protein coupled receptor
5. nerve growth factor (NGF) signaling pathway
Binding interaction between NGF and the TrkA receptor facilitates receptor dimerization and tyrosine residue
of the cytoplasmic tail by adjacent Trk receptors. Trk receptor phosphorylation sites operate as Shc adaptor
docking sites, which undergo phosphorylation by the TrkA receptor. The Trk receptor complex recruits a
adaptor protein called growth factor-receptor bound protein-2 (Grb2) along with a docking protein called
Binder-1 (GAB1) (not shown). Subsequently, phosphatidylinositol-3 kinase (PI3K) is activated, resulting in
6. TrkA
tropomyosin receptor kinase A
7. TrkA is a high affinity receptor involved in
neuronal differentiation and preventing cell death
survival genes
8. p75
neurotrophin receptor
9. p75 is raining expressed in early
neuronal development
promote apoptosis
10. EGF signaling pathway
Signaling pathways and inhibitors of EGFR. Activation of EGFR leads to
phosphorylation of specific tyrosine residues, and recruitment of several proteins at the intracellular portion of
receptors. Phospholipase C (pink) and STAT transcription factors (blue) bind directly to the receptor, whereas
pathway (orange) and PI3K pathway (green) need several specific adaptor molecules (yellow). PI3K can also
directly any of the erbB partners of EGFR heterodimers. Concomitantly, the activated receptors undergo
and follow two possible routes: lysosomal degradation or importin-mediated nuclear translocation. Once in the
EGFR can either behave as a proper transcription factor (for cyclin D1 up-regulation) or as coregulator of
gene transactivators. Both pathways result in nuclear activation of genes related with cell proliferation,
invasion, and metastasis. Two main strategies are available for EGFR kinase inhibition: mAb and
TKIs. mAbs act extracellularly, avoiding EGFR ligands binding, whereas TKIs compete with the ATP binding
the kinase domain of the receptor. DAG, 1,2-diacylglycerol; IP3, inositol 1,3,5-triphosphate; PLC,
C; Erk-1, extracellular signal-regulated kinase-1; Erk-2, extracellular signal-regulated kinase-2; FAK, focal
Biochemistry 2024/25 Edition
