Download The Cell

生命科学基础(3)- 生命的细胞基础
The Cell
KE, Yuehai
柯越海
Zhejiang University, School of Basic medical sciences (BMS-ZJU)
浙江大学基础医学院
Outlines
1. A tour of the cell
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The fundamental units of life
Discovery of cells
Features of cells
Cells and human diseases
Trends of cell biology
2. Cell structure and function: Cell as a life machine
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Overview of cell structure and organelle
Cytoskeleton and membrance
3. Cell communication
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Topics: Cellular membrane and Receptor signaling
Group discussion: novel strategies for target-based anticancer drug discovery
The fundamental units of life
The Chemistry of Life
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Basic chemical context of life: (Hydrogen, Oxygen, Carbon, Nirogen)
Water (H2O): The solvent of life
Carbon: Backbone of life
Carbohydrate: Energy of life
Lipid: Energy storage and hydrophobic membrane
Protein: Diversity of functions
Nucleic acid: A center for heredity
….Cells are as fundamental to the living systems
of biology as the atom is to chemistry…
Discovery of Cells
Robert Hooke
1635-1703
Cell? Yes or No
Robert Hooke
1635-1703
Antoni Van Leeuwenhoek
1632～1723
(1665) R. Hooker ” I took a good clear piece of
Robert Hooke’s double-lens
microscope (1665)
Cork and with a Pen-knife sharpened as keen as a
Razor, I cut a piece of it off, and …, then examining
it … with a Microscope, me thought I could perceive
it to appear a little porous… much like honeycomb ”
Antoni Van Leeuwenhoek’s
single-lens microscope (1673)
(1674) AV. Leeuwenhoek “In structure these little animals
were fashioned like a bell, and at the round opening they
made such a stir, that the particles in the water thereabout
were set in motion thereby. . . And though I must have seen
quite 20 of these little animals on their long tails alongside
one another very gently moving”
Green charophyte alga and Ciliate
by AV. Leeuwenhoek 1674, 1703
Cell theory
Three original tenets of Cell theory
•All organisms are composed by one or more cells
•The cell is the structural unit of life
•Cells can arise only by division from a preexisting cell
Modern interpretation of Cell theory:
Theodor Schwann
(1810-1882)
Rudolf Virchow
(1821-1902)
•The cell is the fundamental unit of structure and function in living things.
•All cells come from pre-existing cells by division.
•Energy flow (metabolism and biochemistry) occurs within cells.
•Cells contain hereditary information (DNA) which is passed from cell to
cell during cell division
•All cells are basically the same in chemical composition.
•All known living things are made up of cells.
•Some organisms are unicellular, i.e., made up of only one cell.
•Others are multicellular, composed of a number of cells.
•The activity of an organism depends on the total activity of independent cells.
•Exceptions
Henrietta Lacks
(1920-1951)
The Immortal Life of
Henrietta Lacks
•Viruses are considered alive by some, yet they are not made up of cells.
Viruses have many features of life, but by definition of the cell theory, they are
not alive.
•The first cell did not originate from a pre-existing cell. There was no exact
first cell since the definition of cell is imprecise.
•Mitochondria and chloroplasts have their own genetic material, and reproduce
independently from the rest of the cell.
The Immortal Life of Henrietta Lacks
by Rebecca Skloot Feb. 5 2010
Five Reasons Henrietta Lacks is the Most
Important Woman in Medical History
Her name was Henrietta Lacks, but scientists know her
as HeLa. She was a poor Southern tobacco farmer…
In 1951, Doctors took her cells without asking, She died
of cervical cancer, and buried in an unmarked grave..
but her cells never died, became one of the most
important tools in medicine.
If you could pile all HeLa cells ever grown onto a scale,
they’d weigh more than 50 million metric tons—as
much as a hundred Empire State Buildings.
Hela cells: The first human cells to be cultured and
currently one of most cell lines in the world
Basic properties of Cells
- Are highly complex and organized
- Possess a genetic program and the means to use it
- Are capable of producing more of themselves
- Acquire and utilize energy
- Carry out a variety of chemical reaction
- Engage in numerous mechanical activities
- Are able to respond to stimuli
- Are capable of self-regulation
Cellular structure
Cells and Human diseases:
Therapy and Stem cell
Basic procedure for cell
replacement therapy
Cells for studying human diseases
Population
Animal (Organ/Tissue)
Human
Cell
Protein /RNA/DNA
Genetic background close to human
Complex factors
In vivo studies & physiological and
pathological phenotypes
High throughput assay
Sample size
 High-costs, low efficiency
Low-cost method
Technically error-prone
Ethnic issue
High-costs
Clinical studies
Hard access to molecular
mechanism
Ethnic issue
High-costs
Not easily accessible
Simple living organism
Lacking physiological functions
Low-cost method
Easy-accessible signal mechanism
Diverse disease-associated models
High-throughput.
Lacking integrated physiological function
Some of features in cells, you may ignore during
research
-Cell-based behaviors and human physiological
function
• Apoptosis, necrosis and autophage
• Proliferation, self-renewal and
differentiation
• Adhesion, migration and invasion
• Endocytosis and phagocytosis
-Diversity of cells: heart, muscle, cancer, neural
cells…
-Cell-cell interaction and microenvironments
-Cell population: quality control and synchronization
-Size of Cells
Trends of Cell Biology
Timeline of developing Biomedical research
Cell and -Omics
Bottleneck for Cytomics:
1. High throughput techniques
2. Powerful data management and functional analysis
3. Integrated, systematic study of complex interactions (Systematic biology)
Outlines
1. A tour of the cell
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•
•
•
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The fundamental units of life
Discovery of cells
Features of cells
Cells and human diseases
Trends of cell biology
2. Cell structure and function
•
•
Overview of cell structure and organelle
Cytoskeleton and membrance
3. Cell communication
•
•
Topics: Cellular membrane and Receptor signaling
Group discussion: novel strategies for target-based anticancer drug discovery
Genetic instructions are housed in the nucleus and
carried out by the ribosomes
Nucleus: Information Center
Ribosome: Protein Factories
Endoplasmic Reticulum: Biosynthetic
Factory
The Golgi Apparatus:
Shipping and Receiving Center
Lysosomes: Digestive Compartments
Mitochondria changes energy from one form
to another
1. A tour of the cell
2. Cell structure and function: Cell as a life machine
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Overview of cell structure and organelle
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Nucleus and Ribosome: A house for genetic instruction
Endoplasmic Reticulum: Biosynthetic factory
Golgi Apparatus: Shipping center
Lysosomes: Trash bin
Mitochondria: Energy processer
Cytoskeleton: Morphology and Mobility
Membrane: Guard and more…
Cytoskeleton and membrance
3. Cell communication
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•
Topics: Cellular membrane and Receptor signaling
Group discussion: novel strategies for target-based anticancer drug discovery
Moving cells
(片状伪足)
(丝状伪足)
Cytoskeleton
(细胞骨架):
Cytoskeleton
Microfilaments (微丝)
Intermediate filaments
(中等纤维)
Microtubules (微管)
Cytoskeleton:
three primary polymer systems
Microtubules
tubulin
Microfilaments
phalloidin
Intermediate filaments
vimentin
Key to cytoskeletal functions
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Structure and mechanical integrity
Intracellular transport
Cell movements
Spatial organization
Microtubules (微管)
• Cylindrical tubes, 20-25 nm in diameter.
• Subunits: alpha-, beta-tubulin(微管蛋白) and MAP (tau)
• Scaffold system to determine cell shape
• Tracks system for cell organelle and vesicle movement.
• Dynamic instability (动态不稳定)
Microtubule structure
MT assembling and dynamics
Dynamic instability
Tau MAP protein and Alzheimer's disease
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Tau is one of the microtubule-associated proteins (MAPs) that stabilize neuronal
microtubules for their role in the development of cell processes.
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Hyperphosphorylated Tau may contribute to a destabilized microtubule network,
,
paired helical filaments (配对螺旋样纤维 PHL), and ultimately in neurofibrillary
tangle (神经纤维缠结, NFT) formation and neuronal death.
Assembly inhibiting agents
Microfilaments (微丝):
• Finest, thread-like protein fibers, 3-6 nm in
diameter.
• Actin (肌动蛋白), the most abundant cellular
protein, G-actin F-actin.
• Responsible for muscle contraction and cell
movements.
Actin monodimer structure
Actin branching structures
e.g. α-actinin
ARPs (Actin-related rpoteins)
Actin creates gross morphological change in
platelet cells
Critical issues
•Quantitative measurement
•Living cells (Non-invasive tools)
•Mathematical and statistic model
Central roles of cytoskeletal rearrangement in the
variety of cell physiology
Thomas DP., Science 2009
Intermediate filaments (中等纤维)
• Stable, durable, 10 nm in diameter
• Subunit: keratin, vimentin, glial fibrillary acidic protein (GFAP),
neurofilaments(NF)
• Mechanical support for the plasma membrane
• Do not participate in cell motility
• Unique to different tissue types, potential application to identify
the cellular origin of certain tumors
Intermediate filaments assembling
Intermediate filaments：Useful
biomarkers
• Nestin (巢蛋白): neuroectoderm, neural stem/progenitor cells,
melanomas, gliomas
• GFAP (胶质纤维碱性蛋白): astrocyte/glial cells
• Keratin (角蛋白): major structural proteins in epithelial cells
• Vimentin (波形蛋白): mesenchymal marker
• Neurofilaments (神经丝蛋白) : neuronal marker
Summary of cytoskeleton
Motors and intra-cellular movement
• Motor proteins(马达蛋白): use ATP hydrolysis to move along
filaments (actin or microtubules)
• Myosin (肌球蛋白): binding with microfilaments
• Dynein or Kinesin: binding with microtubules
• Myosin and kinesin(驱动蛋白) superfamilies are very diverse
– the common element is head group
– there are many different tails for different cargos
• Myosin/actin system powers contraction of muscle
Myosin (肌球蛋白),Kinesin (驱动蛋白),Dynein (动
力蛋白)
Cell movement
1. Polarization.
2. Protrusion
3. Traction
4. Retraction
Moving with actin-dependences
Lamellipodium
Lamellipodia, Filopodia and Stress fibrers
(片状伪足、丝状伪足、应力纤维)
A working model for filopodia/ lamellipodia formation (I)
Actin nucleation
ARP2/3 complex: Actin filament nucleator
WASP proteins: W-A syndrome protein , Filament nucleation and elongation.
Profilin: Recruits G-actin
Formins: Initiates filament assembly
Protecting the end from capping proteins
A working model for filopodia formation (II)
Protrusion
Capping protein: Inhibiting polymerization of actin filament
ENA/VASP: Enable/vasodilated-stimulated phosphoprotein,
promote actin filament elongation, anti-branching
Fascin: F-actin-crosslinking protein of filopodia
IRSp53: Deforms membranes to
promote the formation protrusions
Dia2: Unbranched actin filaments in filopodia
Myosin-X: Filopodia formation by
transporting proteins to filopodial tips
Ena/VASP null cells
No filopodia
Cell mobility and tumor metastasis
Podosomes and Invadopodia
Podosomes : Ring-Shape of degradation of ECM
Invadopodia: Irregular dots of degradation of ECM
Podosomes in normal cells
Primary human
macrophage
Vascular smooth muscle
cell
Human umbilical vein
endothelial cell
Invadopodia in oncogenic cells
Podosomes /Invadopodia in Srctransformed fibroblasts
Invadopodia in melanoma
Comparison of Podosomes and Invadopodia
Sara Courtneidge
Professor, Sanford-Burnham Medical
Research Institute/ UCSD
Anne J. Ridley
Randall Division of Cell and Molecular Biophysics,
King’s College London, New Hunt’s House,
Guy’s Campus, London, United Kingdom
Cytoskeleton-dependent movement
Electron micrograph exhibits protrusions at leading edge
generated by actin polymerization
Polarized movement
Adhesive movement
Features of Cell Movement
• Requires cooperation among filaments and motors
• Requires sustained polarity which is influenced by
external cues
• Coordinated with adhesion of protrusion, traction via
motors, and disassembly of cell-substratum contacts
Central roles of Cytoskeleton
•Morphology
•Adhesion
•Migration
•Polarity
•Invasion
•Trafficking
•Transportation
•Endocytosis
•Exocytosis
•vesicular transport
•Division
•Autophage
•Apoptosis
•…
Subcellular
•Embryogenesis and organogenesis
•Malignant metastasis of cancer
•Pathogenic infection
•Immunity and inflammation
•Synapse plasticity
•Drug Discovery
Cellular
Tissue, organ and human
Mini-Quiz

Which of the following cytoskeleton is less likely to be responsible for cell
movements?
A. Microtubules
B. Microfilaments
C. Intermediate filaments
D. Kinesin

Which of the following cytoskeleton has unique features for assembling and
disassembling named as dynamic instability.
A.
C.

Microtubules
Intermediate filaments
B. Microfilaments
D. All of them
The best description for energy generator of motor proteins to power cell motility
is
A. ATP hydrolysis
B. Phosphorylation
C. Oxidation
D. Dephosphorylation
1. A tour of the cell
2. Cell structure and function: Cell as a life machine
•
Overview of cell structure and organelle
−
−
−
−
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Nucleus and Ribosome: A house for genetic instruction
Endoplasmic Reticulum: Biosynthetic factory
Golgi Apparatus: Shipping center
Lysosomes: Trash bin
Mitochondria: Energy processer
− Cytoskeleton: Morphology and Mobility
 Cytoskeleton: Microtubules, Microfilaments, Intermediate filaments
 Cell movement: Cytoskeleton-dependence, Polarity, Adhesion
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Membrane: Guard and more…
3. Cell communication
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•
Topics: Cellular membrane and Receptor signaling
Group discussion: novel strategies for target-based anticancer drug discovery
Overview of membrane
Functions of transmembrane proteins
1. Transport
2. Enzyme
Passive and active transport
The structure of a transmembrane protein
The first ARG (AIDS Restriction
Gene) gene identified in 1996
3. Signal transduction (Intralcellular)
4. Cell-cell recognition
Dr Stephen J
O’Brien
The structure of a transmembrane protein
5. Signal transduction (Inter-cellular)
6. Attachment to ECM
EMC and Cancer
migration/invasion/Metastasi
s
Synthesis of membrane
Phagocytosis, Pinocytosis and Endocyosis
1. A tour of the cell
2. Cell structure and function: Cell as a life machine
•
Overview of cell structure and organelle
−
−
−
−
−
Nucleus and Ribosome: A house for genetic instruction
Endoplasmic Reticulum: Biosynthetic factory
Golgi Apparatus: Shipping center
Lysosomes: Trash bin
Mitochondria: Energy processer
− Cytoskeleton: Morphology and Mobility
 Cytoskeleton: Microtubules, Microfilaments, Intermediate filaments
 Cell movement: Cytoskeleton-dependence, Polarity, Adhesion
− Membrane: Guard and more…
 Transport, Enzyme, Intral/internal cellular communication, Cell-cell
recognition, attachment to ECM;
 Synthesis
 Phagocytosis, Pinocytosis and Endocyosis
3. Cell communication
•
•
Topics: Cellular membrane and Receptor signaling
Group discussion: novel strategies for target-based anticancer drug discovery
课后安排
•Critical readings:
•Teaching PPTs (PDF)
•Text book (Campbell biology 9th ) The Cell: A Tour of the Cell and Page
140-170;
•General readings: Text book (Campbell biology 9th ) The Chemistry of Life Page 74-137
•Pollard TD, Cooper JA. Actin, a central player in cell shape and movement
Science. 2009 Nov 27;326(5957):1208-12. Review
•Cell and Molecular Biology: Concepts and experiments GERALD KARP et al., the 4th Edition,
高等教育出版社(英文影印版), ISBN 978-7-04-019174-5
•第九章 细胞骨架与细胞运动
•分子细胞生物学 Gerald Karp 王喜忠 主译 第三版 高等教育出版社 （中文翻译版） ISBN 7-04015850-7
•Chaptor 9 The Cytoskeleton and Cell Motility