Lecture 3 Pathways to Networks

3.A MAP-kinase pathways

1. Example: interactions between the cAMP and MAPK pathways
2. Assembling Signaling Complexes: Adaptors such as Grb2 and Crk, and exchange factors (GEFs) such
   as SOS and C3G are assembled as extracellular signals such as epidermal growth factor (EGF) arrive to enable the receptor that activates the GTPases Ras or Rap
3. A large network can emanate from a single receptor
4. There are 3 major MAPK pathways : ERK, JNK and p38.
5. Growth factor signaling from cell surface membrane to nucleus
6. Compartmental Models & Partial Differential Equations (PDEs)

3.B MAP-kinase network

1. 连接Pathways以形成network
2. For many growth factor receptors like EGFR (epidermal growth factor receptor) The ability to interact with multiple effectors Grb2/SOS/RAS, PI3Kinase, PLCγ, STATs allow the receptor to regulate a large network of effectors
3. Epinephrine & Norepinephrine的三种Pathway
4. A single ligand (hormone) through multiple receptors can engage a network due to cross connectivity
5. cAMP接受多种因子的调控
6. Small GTPases enable networking by acting through multiple pathways reach different effectors
7. The ability of a protein kinase to phosphorylate many substrates, such as transcription factors, leads to cross–connectivity that creates extensive networking

Lecture 4 Mechanical Forces in Cell Biology

4.A Mechanical Forces in Cell Biology

 Interactions between specific proteins lead to formation of filaments纤维 and other structures that are capable of generating mechanical forces机械力
 Force generation within cells can be analytically modeled分析建模
 Interaction of molecular motors分子马达 with filaments纤维 are involved in force generation
 Force generation by actin filaments肌动蛋白微丝 is regulated by cell signaling networks, and conversely force signals can be sensed (mechanotransduction力传导) by these same networks
 Hybrid models can be used to study how signaling networks regulate cell spreading through control of force generation

4.B Electrical activity in Cell Biology

The ability of plasma membrane质膜 to act as a barrier to ion flow 离子屏障enables the generation of electrical properties. The membrane acts as a capacitor电容.
 Cells such as neurons and muscle cells have ion channels 离子通道that enable asymmetric distribution 非对称of ions, giving rise to membrane potentials膜电位.
 Resting membrane potentials 静息膜电位can be changed in a controlled manner, giving rise to action potentials动作电位 that can travel along the cell membrane细胞膜.
 Mathematical models can accurately describe the generation and propagation传导 of action potentials. Classical H&H model was among the earliest (1952) in applying mathematical reasoning in biology
 Biochemical and electrical signaling are extensively connected.广泛地联系起来 This can give rise to complex computation and emergent information processing