Cell signaling pathways: growth factors Flashcards
(51 cards)
what are growth factors
substances capable of inducing cell growth, proliferation, healing, and/or differentiation
what are the major types of growth factors
proteins and steroids
where do proteins bind
on surface of cell membrane
where do steroids bind
on cytoplasmic, nuclear receptors
what are the major families of growth factor receptors
tyrosine kinase activity, serine/threonine kinase activity, and GPCRs
what role do growth factors play in the body
embryonic growth, cell survival, and in wound healing in adults
what can the nerve growth factor (NGF) bind to
tropomyosin(TrkA) receptor or p75MTR
what are the effects of NGF binding to trkA
involved in neuronal differentiation and preventing cell death
what is the pathway for epidermal growth factor signaling
activation of EGFR leads to dimerization and recruitment of proteins like PLC and STAT transcription factors or PI3K binds with adaptor proteins. both of these pathways go to the nucleus to affect gene transcription
what are the 4 subfamilies of the TGF beta superfamily
-TGF beta subfamily
- decentaplegia (Dpp) related subfamily
-actin and inhibin subfamily
- fourth subfamily of diverse members
what is included in the decapentaplegic (Dpp) subfamily
BMPs and growth differentiation factors
what do activin and ibhibin subfamily of TGF beta superfamily do
regulate sex and organ development
what do proto-oncogenes do
encode growth factors and transcription factors to carry out normal growth, proliferation and survival
how are the majority of growth factors translated
as a pro-form and then undergo proteolytic processing steps by members of the proprotein convertase family of enzymes
what is furin
a proprotein convertase
what is furin involved in
-neuronal innervation
-control of juxtacrine and paracrine signaling
- cartilage breakdown
- tumor metastasis
what happens in neuronal innervation the pro beta NGF is cleaved by furin
neuronal innervation and survival
what happens to pro beta NGF when it is not cleaved by furin
apoptosis
what happens in signaling when EDA-1 is cleaved by furin
paracrine signaling
what happens in signaling when furin does not cleave EDA-1
juxtacrine signaling
what happens in cartilage breakdown with furin
furin cleaves and leads to the degradation of cartilage proteins
what happens in tumor metastasis with furin
furin cleaves a protein and results in tumor metastasis
how is TGF beta synthesized and released
the precursor undergoes dimerization and cleavage that results in a small latent complex and a large latent complex. the large complex in stored in ECM through the binding of the RGD motif to integrins and active TGF beta is released
what happens when TGF beta binds to its receptor
they bind to a specific type 2 receptor subunit which recruits a type 1 subunit. this results in phosphorylation of the recruited type 1 receptor which then phosphorylates a receptor regulated SMAD protein in the canonical/classical pathway
