Cell signaling

examples of signals

temperature, pressure, (physical); hormones, cytokines (chemical)

general types of signaling

paracrine (close), endocrine (far, bloodstream), autocrine (same cell), plasma membrane (or ECM) attached cells

what does direct intracellular signaling mean

gap junctions!

where are steroid hormones (e.g.) estrogen received

cytoplasmic receptors, hormones small and can pass through

where are cytokines (proteins) received

plasma membrane receptors, large and cannot get through

types of direct acting signal responses

transcriptional responses, activation of ezymatic activity (RTK), activation of channel proteins

types of indirect responses

signalling cascades, signal releases something that binds to something else causing it to release other signals

how to signaling cascades work

signal - receptor - transduction - secondary messengers/intracellular signaling proteins - target proteins - cellular responses - feedback inhibition (termination)

what is cAMP

2ndary messenger, adenylyl cyclase turns ATP into cAMP, starts in cytosol

what are IP3 and DAG

2ndary messengers, start as PIP2, phospholipase cleaves their shi, starts in membrane

how to ECM proteins end up outside the cell

they go through the endomembrane system and are exported by exocytosis

functions of the ECM

separates cells, tissues, and cell layers, semi-permeable barrier, activates signals that regulate cell function

what proteins make up the ECM

collagen, laminin, proteoglycans (i.e. cartilage)

laminin

primary component of basal lamina of epithelial cells

what is cross talk

a part of one signaling cascade having an effect on another

broad categories of signal response

activation of proteins that already exist, change in gene expression

what does cAMP do

alters metabolism, transcription, enzyme function