Website Search
ID 1018

Pathways, At the cell surface

In this section learn that a signaling pathway begins with the arrival of a chemical signal - such as a hormone or growth factor - at the cell surface.
A signaling pathway begins with the arrival of a chemical signal – such as a hormone or growth factor – at the cell surface. The gray structures sticking out of the cell membrane are receptors for these incoming signals. The signal, in this case a platelet-derived growth factor (here in purple and blue), encounters and binds to its matching receptor. A second receptor protein joins in, making the growth factor fit like a key in a lock. The binding of the growth factor causes the receptors to change shape. This change in the protein will be conducted through the membrane and into the cell's interior – the cytoplasm. Molecules identified: Platelet derived growth factor (PDGF): PDGF stimulates growth and division in cells such as fibroblasts and smooth muscle cells. PDGF is important in tissue repair, activating cells of the immune system and synthesizing components of the extracellular matrix. Some cancer cells produce their own PDGF, which releases them from their dependency on growth signals from other cells. Platelet derived growth factor (PDGF) receptors: PDGF receptors are large membrane-spanning proteins with an extracellular and an intracellular component. Two PDGF receptor proteins "dimerize" to bind a single platelet-derived growth factor. The cytoplasmic portion has kinase activity – able to add phosphate molecules to other molecules to activate them. This receptor can contribute to cancer if rendered active for an extended period of time.
smooth muscle cells, pdgf receptor, platelet derived growth factor, cells of the immune system, receptor proteins, cancer cells, incoming signals, receptor protein, chemical signal, extracellular matrix, cell surface, tissue repair, cell membrane, cytoplasm, phosphate, period of time
Creative Commons License This work by Cold Spring Harbor Laboratory is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.

Related content:

1019. Pathways, Beneath the membrane
In this section learn that the binding of growth factors outside the cell causes receptors ends to intertwine and activate each other, and once active, the modified receptor ends interact with messenger proteins.
1020. Pathways, A bevy of interactions
In this section learn that receptors activate each other before binding an adaptor molecule and an exchange factor.
1024. Pathways, Releasing the protein
In this section learn that newly made proteins leave the endoplasmic reticulum wrapped in a layer of membrane called a vesicle.
16877. Cell Signals
Journey inside a cell as you follow proteins and learn about cellular interactions. This 3-D animation brings to life the inner workings of a fibroblast cell as it responds to external signals. Created by Cold Spring Harbor Laboratory and Interactive Know
16724. Concept 35: DNA responds to signals from outside the cell.
Signal transduction is cell communication that involves a series of molecular transformations.
959. Causes, Smoking: K-ras
This section explains how the protein produced by the K-ras gene is a tumor “activator.”
1069. Receptor Molecules
Professor David Van Vactor describes the role of receptor molecules, which receive signals from outside the cell, passing the signal to the inside.
1816. PTK2B/A0030
PTK2B, also known as PYK2 or A0030, is a member of the focal adhesion kinase (FAK) family.
1011. Diagnosis, Targeted therapies: Blocking receptors
In this section, hear what experts have to say about drugs that disrupt the function of receptors on a cell's surface.
15959. What is Neurofibromatosis 1?
NF1 is a large gene that encodes three slightly different neurofibromin proteins, found in nerve and muscle tissue
Cold Spring Harbor Laboratory
CSHL HomeAbout CSHLResearchEducationNews & FeaturesCampus & Public EventsCareersGiving