SLIDE 1
Plasma membrane microdomains
- rganize biochemical reac2ons to
T cell membrane microdomains: dynamic and fluid structures
Douglass and Vale
Plasma membrane microdomains organize biochemical reac2ons to - - PowerPoint PPT Presentation
Plasma membrane microdomains organize biochemical reac2ons to - - PowerPoint PPT Presentation
Plasma membrane microdomains organize biochemical reac2ons to transduce signals Yoshihisa Kaizuka Na2onal Ins2tute for Materials Science University of California, San Francisco T cell membrane microdomains: dynamic and fluid structures
SLIDE 2
SLIDE 3
Modula2on of molecular conforma2ons‐ func2ons by lateral organiza2ons
Receptor enriched membrane microdomain
T cell
Lck
SLIDE 4
Signal transduc2on in T cell ac2va2on
TCR Lck
CD4 LFA CD8 CD28 PI3K Fyn
ZAP70
Itk MEK
CD45
CD148 PTEN
LAT
SLp76 Nck Grb2 PKC Orai STIM PLCg1 Ras Sos ERK JNK IKK Nucleus NFAT NFkB Jun etc. Ca IP3 DAG IP3R PIP2 Actin Rac Cdc42 WASP WAVE RasGRP talin
T Cell
ER CD2
Antigen
Antigen presenting cell
SLIDE 5
Cri2cal kinase Lck is ac2vated on plasma membrane
TCR Lck CD45
T Cell
How is Lck ac2vated?
Lck (src kinase) – CD45 (phosphatase) – Receptor
SLIDE 6
How is Lck ac2vated in T cell? How is Lck opened in T cell? (release of autoinhibitory interac2ons)
SH3 SH2 membrane
Lck Inactive Lck Active
Catalytic domain Loop
Phospho- tyrosine
SLIDE 7
Model: Locally Concentrated Receptors Ac2vate Lck by Releasing Autoinhibitory Interac2ons
Receptor enriched membrane microdomain
T cell
Lck
SLIDE 8
Imaging T Cell membrane microdomains
Ligand for T cell
Side View
Glass substrate
- Mimic cell-cell interaction
- Biochemical control
- Surface-based imaging
(TIRF, confocal)
SLIDE 9
Microdomain forma2on in ac2vated T Cell membranes
5µm
- Functional assays show T cell is activated upon
microdomain formations, suggesting Lck activation.
- How does Lck activation occur?
SLIDE 10
Lck is ac2vated in microdomains
Wildtype Lck Open form mutant Lck (Y505F) 2µm GFP GFP GFP inactive active
microdomains microdomains
SLIDE 11
Mechanisms for Ac2ve Lck Localiza2on (1)
Receptor cytoplasmic domain is required for Lck activation
Open Lck enrichment in microdomain Cytoplasmic domain deletion
microdomains
SLIDE 12
Dynamic and transient ac2va2on of Lck in microdomains facilitates T cell ac2va2on
TCR Lck
SLIDE 13
Mechanisms for Ac2ve Lck Localiza2on (2)
Phosphatase CD45 is excluded from microdomain CD45 as a negative regulator
Lck CD45
microdomains
SLIDE 14
Localized Ac2ve Lck Facilitates Downstream Signaling
microdomains merge
SLIDE 15