Transcript April 25th powerpoint

BIO409/509 Cell and Molecular Biology
[email protected]
subject: Pre-Med Social this Thursday
There will be a social hour for pre-med students this
Thursday, April 28th, from 4:00 to 5:00 PM in the Fishbowl
(room 153 Science Building). The purpose is to say hello to
other pre-med students and network to gain info about the
pre-med pathway. We'll be hosting Dr. Fred Fridman. Fred
graduated from USM a few years ago and has just returned
to begin practicing medicine at New England Rehabilitation
Hospital and Maine Medical Center. Please come to say
hello. We have a great group of pre-meds at USM and there
are probably some you don't know yet. Bring food to share if
you'd like. That would be great. Thanks!
BIO409/509 Cell and Molecular Biology
The final exam will cover material from
class since the second exam plus:
Ch 8 RNA
Ch 9 proteins
Ch 10 nucleus
Ch 11 protein sorting and transport
(probably) Ch 13 cytoskeleton
9
Protein Synthesis,
Processing, and Regulation
Figure 9.9 Overview of translation
Figure 9.30 The role of signal
sequences in membrane translocation
Figure 9.23 Action of chaperones
during translation
Figure 9.25 Sequential actions of
chaperones
Figure 9.28 The action of protein
disulfide isomerase
Post-translational regulation
is a term not often used
Post-translational modifications
are a subset of the above.
This term is often used.
Figure 9.33 Synthesis of N-linked
glycoproteins
Figure 9.31 Proteolytic processing of
insulin
Figure 9.38 Structure of a GPI anchor
Regulation of Protein Function
• Cells can regulate the amounts and the
activities of their proteins.
• Three mechanisms:
• Regulation by small molecules
• Phosphorylation and other modifications
• Protein-protein interactions
Figure 9.43 Modification of proteins
by small molecules (Part 1)
Figure 9.44 Modification of proteins
by ubiquitin
Figure 9.46 The ubiquitin-proteasome
pathway
Figure 9.47 Cyclin degradation during
the cell cycle
Figure 9.48 Autophagy
Figure 9.41 Protein kinases and
phosphatases
Changes in sensitivity of target cells to estrogen include
changes in the estrogen receptor and more.
10
The Nucleus
10 The Nucleus
• The Nuclear Envelope and Traffic
between the Nucleus and the Cytoplasm
• The Organization of Chromosomes
• Nuclear Bodies
Introduction
• The nucleus is the main feature that
distinguishes eukaryotic from prokaryotic
cells.
• It houses the genome, and thus is the
repository of genetic information and the
cell’s control center.
• Separation of the genome from the site of
mRNA translation plays a central role in
eukaryotic gene expression.
The Nuclear Envelope and Traffic
between the Nucleus and the
Cytoplasm
• The nuclear envelope separates the
nuclear contents from the cytoplasm.
• It controls traffic of proteins and RNAs
through nuclear pore complexes, and
plays a critical role in regulating gene
expression.
The Nuclear Envelope and Traffic
between the Nucleus and the
Cytoplasm
• The outer membrane is continuous with
the endoplasmic reticulum (ER).
• The space between inner and outer
membranes is directly connected with the
lumen of the ER.
• The inner membrane has integral
proteins, including ones that bind the
nuclear lamina.
Figure 10.1 The nuclear envelope
(Part 1)
Figure 10.1 The nuclear envelope
(Part 2)
Figure 10.1 The nuclear envelope
(Part 3)
Figure 10.4 Lamin assembly
Figure 10.3 Electron micrograph of the
nuclear lamina
The Nuclear Envelope and Traffic
between the Nucleus and the
Cytoplasm
• Mutations in lamin genes cause several
inherited tissue-specific diseases.
• The bases of the pathologies in each of
these diseases is still unclear.
Molecular Medicine, Ch. 10, p. 371
Figure 10.5 The nuclear lamina
Figure 10.6 Molecular traffic through
nuclear pore complexes
The Nuclear Envelope and Traffic
between the Nucleus and the
Cytoplasm
• Electron microscopy shows pore
complexes have eight subunits organized
around a large central channel.
Figure 10.7 Electron micrograph of
nuclear pore complexes
The Nuclear Envelope and Traffic
between the Nucleus and the
Cytoplasm
• Eight spokes are connected to rings at the
nuclear and cytoplasmic surfaces.
• The spoke-ring assembly surrounds a
central channel.
• Protein filaments extend from the rings,
forming a basketlike structure on the
nuclear side.
Figure 10.8 Model of the nuclear pore
complex
Figure 10.13 mRNA export