Signal Transduction
Definition
How a signal arriving at a cell surface becomes a change inside the cell: receptor binding, a relay of intracellular messengers, and an effect on enzyme activity or gene expression. Amplification at each stage is why a small number of bound receptors produces a large response.
What this means for research sourcing
Signaling terms describe how peptides exert effects at the receptor level in vitro. Volta's research library and mechanism pages map these pathways to stocked compounds.
Related Terms in Signaling Pathways
Downstream Effect
A consequence occurring later in a pathway than the point a compound acts on. The further downstream an observation sits, the more other inputs have had a chance to influence it.
NF-κB (Nuclear Factor Kappa B)
A transcription factor complex that switches on inflammatory genes, held inactive in the cytoplasm until a signal releases it. KPV, BPC-157 and Thymosin Alpha-1 are all studied for suppressing it, and cytokine output is the readout.
PI3K/AKT/mTOR Pathway
The cascade through which growth factors including IGF-1 and insulin control growth, metabolism, survival and protein synthesis. Anabolic peptides act through it. Inhibiting mTOR, as rapamycin does, is a separate longevity strategy pointing the other way along the same pathway.
AMPK (AMP-Activated Protein Kinase)
The cell's energy sensor, activated when the AMP to ATP ratio rises under exercise or fasting, shifting metabolism toward glucose uptake, fat oxidation, mitochondrial biogenesis and autophagy. MOTS-c activates it; AICAR does so indirectly through its intracellular metabolite ZMP and is a nucleoside rather than a peptide.
CREB (cAMP Response Element-Binding Protein)
A transcription factor switched on downstream of cAMP, central to synaptic plasticity, memory formation and neuronal survival. Semax and Dihexa are studied for effects on CREB-dependent gene expression.
BDNF (Brain-Derived Neurotrophic Factor)
A neurotrophin supporting neuronal survival, dendritic growth and synaptic plasticity. It is the most frequently cited mechanism for nootropic peptide claims and is usually measured in rodents, which is the main limitation on reading those claims across to humans.
SNARE Complex
The protein machinery, SNAP-25 with VAMP and syntaxin, that fuses transmitter vesicles with the cell membrane so their contents are released. Botulinum toxin cleaves SNAP-25; the cosmetic peptide SNAP-8 is named for interfering with assembly of the same complex.
JAK/STAT Pathway
The route by which cytokines, interferons and several growth factors turn receptor binding into changed gene expression, with a kinase phosphorylating a transcription factor that then moves to the nucleus. Immunomodulatory peptide work measures it.