BI 431 Plant Phys Ch. 12

Northern Michigan University Dr. Maki

Second messenger

Small intercellular molecule that increases or decreases in concentration in response to the activation of a receptor/ produces a change in gene expression

Signal transduction pathway

Sequence of biochemical processes by an extracellular signal interacting with a receptor/ causes release of second messenger and eventually a change in cell function

Cell autonomous response

A response to an environmental stimulus that is localized to a specific cell

Non-cell autonomous response

Cellular response to an environmental stimulus that is induced by other cells

Kinases

Phosphorylating enzymes

MAP kinase cascade

Series of protein kinases that transmit an activation signal from a receptor to DNA in the nucleus

Proton motive force

Energetic effect of an electrochemical gradient, from protons, across a membrane

Reactive oxygen species

Generated in the cell as a signal and may cause damage to cellular components

Auxins (IAA)

Group of plant hormones involved in cell elongation, differentiation, and apical dominance/ creates uneven growth when one side of the plant is exposed to light/ synthesized in the stem apical and transported through the phloem

Gibberellins

Group of plant hormones associated with stem growth and seed germination/ makes plants very tall!

Cytokinins

Class of plant hormones that affect cell wall division and differentiation (growth stimulator)/ stops leaf senescence

Ethylene

Gaseous plant hormone involved in ripening and leaf abscission/ oxygen is needed for synthesis/ synthesized in response to stress

Abscisic acid

Plant hormone that regulates seed dormancy and water stress responses/synthesized in chloroplasts

Brassinosteroids

A group of plant hormones that help with sex determination, cell elongation, and division

Salicylic acid

Serves as a signal systemic acquired response

Jasmonic acid

Plant hormone that functions in plant defenses and may be a volatile signal

Strigolactones

Plant hormone that inhibits shoot branching/ stimulates germination of parasitic plants

ACC synthase

+ AdoMet = ACC

ACC oxidase

+ ACC = ethylene

Two-component regulatory system

Signaling pathway that uses a kinase sensor protein and a response regulator protein that creates the response in the cell

Sensor proteins

Membrane receptor proteins that have an input and a transmitter domain

Response regulator

Carries out the response after being phosphorylated by the sensor kinase protein

Ubiquitin-proteasome pathway

Specific mechanism for the degradation of cellular proteins

Cross-regulation

Interaction of 2+ signaling pathways

Systems biology

Science of complex living processes and mechanisms

Scheme of signal transduction

Environmental signal→ receptor→ cellular signal amplification→ signal transmission→ response

Calcium

Large player as a second messenger

Free lipids

Act as a second messenger when a plant is being chewed on and the cell wall breaks down

Electrical signaling

Uses action potentials for long-distance signal transport