rav65819_ch09_165-184

rav65819_ch09_165-184 - ; 9 chapter Cell Communication...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
;;;;;;;; 9 chapter Cell Communication introduction
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
SPRINGTIME IS A TIME OF REBIRTH and renewal. Trees that have appeared dead produce new leaves and buds, and flowers sprout from the ground. For sufferers of seasonal allergy, this is not quite such a pleasant time. The pollen in the micrograph and other allergens produced stimulate the immune system to produce the molecule histamine and other molecules that form cellular signals. These signals cause inflammation, mucus secretion, vasodilation, and other responses that together cause the runny nose, itching watery eyes, and other symptoms that make up the allergic reaction. We treat allergy symptoms by using drugs called antihistamines that interfere with this cellular signaling. The popular drug loratadine (better known as Claritin), for example, acts by blocking the receptor for histamine, thus preventing its action. We will begin this chapter with a general overview of signaling, and the kinds of receptors cells use to respond to signals. Then we will look in more detail at how these different types of receptors can elicit a response from cells and finally how cells make connections with one another. concept outline 9.1 Overview of Cell Communication Signaling is defned by the distance From source to receptor Signal transduction pathways lead to cellular responses Phosphorylation is key in control oF protein Function 9.2 Receptor Types Receptors are defned by location Membrane receptors include three subclasses Membrane receptors can generate second messengers 9.3 Intracellular Receptors Steroid hormone receptors aFFect gene expression Other intracellular receptors act as enzymes 9.4 Signal Transduction Through Receptor Kinases RTKs are activated by autophosphorylation Phosphotyrosine domains mediate protein–protein interactions Protein kinase cascades can ampliFy a signal ScaFFold proteins organize kinase cascades Ras proteins link receptors with kinase cascades RTKs are inactivated by internalization 9.5 Signal Transduction Through G Protein-Coupled Receptors G proteins link receptors with eFFector proteins EFFector proteins produce multiple second messengers DiFFerent receptors can produce the same second messengers
Background image of page 2
Receptor subtypes can lead to different effects in different cells G protein-coupled receptors and receptor tyrosine kinases can activate the same pathways 9.6 Cell-to-Cell Interactions Surface proteins give cells identity Cell connections mediate cell-to-cell adhesion 165 rav65819_ch09_165-184.indd 165 rav65819_ch09_165-184.indd 165 11/15/06 3:25:31 PM 11/15/06 3:25:31 PM 9.1 Overview of Cell Communication Communication between cells is common in nature. Cell signaling occurs in all multicellular organisms, providing an indispensable mechanism for cells to influence one another. Effective signaling requires a signaling molecule, called a ligand, and a molecule to which the signal binds, called a
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/15/2010 for the course BIO BIO1 taught by Professor Lipke during the Fall '09 term at CUNY Brooklyn.

Page1 / 227

rav65819_ch09_165-184 - ; 9 chapter Cell Communication...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online