Signal Transduction Test 2 Flashcards
Signaling requires a ligand induced clustering of receptors called ____.
cross linking
Intergrins and Src Kinases use what kind of receptor?
Non receptor tyrosine kinase
EGF and Insulin use what kind of receptor?
RTK
Vitamin D and Glucocorticoids use what receptor?
Nuclear hormone receptor. These are lipid soluble and can pass through the membrane to the nucleus to initiate transcription of nuclear hormone target gene
Chemokines and prostaglandins use what receptor?
GPCR
Delta and delta like notch ligands use what receptor?
Notch
What kind of enzyme plays an inhibitory role?
Phosphatases
How can protein modifications impact signal transduction?
Covalent addition of Ubiquitin targets proteins for degradation or drives signal transduction in many cells.
Protein signaling molecules can also be modified by addition of lipids covalently.
What two things are modular proteins built from?
Combinations of interaction domains and catalytic domains
Tyrosine Kinase family Src (Lyn and Lck) has what two domains and what do they bind to?
SH3: proline rich peptides
SH2: phosphotyrosine
Tyrosine Kinase family Syk (Syk and Zap-70) have what domains and what do they bind?
Two SH2 which binds to phosphotyrosine
Tyrosine Kinase family Tec (Btk and Ltk) have what three binding domains and what do they bind?
SH2:phosphotyrosine
SH3: proline rich peptides
PH: binds phospholipids such has IP3
Btk tyrosine recognizes a lipid moiety called ___.
PIP3
Characteristics of Adaptor proteins?
NO catalytic activity
Contain only protein protein interaction domains
Physically link different enzymes and promote assembly of complexes of signaling molecules such as LAT and BLNK
What is LAT?
T cell linker protein for activating T cell signaling
Type of adaptor protein, it is an integral membrane protein
What is BLNK?
B cell linker, adaptor protein for B cell signaling
What is the significance of LAT and BLNK?
They are critical for B and T cell signaling, without LAT there will be no mature T cells
After phosphorylation what does LAT do?
Recruits PLC-Y and GADS
What is SLP-76?
Adaptor in T cell activation. Its proline rich and binds with SH3 domain on GADS leading to the phosphorylation of tyrosine residue
What is VAV?
Adaptor in T cell activation. Recruited by the phosphorylation of the tyrosine residue done by SLP-76. It is a GEF and will replace GDP with GTP activating enzymes/TF
Describe Adaptors in T cell activation together.
When LAT is phosphorylated it recruits PLC-y and GADS adaptor protein. THen SLP-76 associates with GADS via SH3 domain and recruits VAV after being tyrosine phosphorylated. VAV proteins are GEF’s and activate actin cytoskeletal rearrangements and transcriptional alterations
What proteins serve as signaling transducing subunits of TCR complex?
CD3 and Zeta proteins
Zeta chain has 6 ITAMs and CD3 has 2
Where are ITIMs commonly found?
FcyRIIB on B cells and myeloid cells
Describe structure of CD4.
Four extracellular Ig like domains, hydrophobic transmembrane region, highly basic cytoplasmic tail
Describe CD8 structure
Composed of two related chains called CD8alpha and CD8beta, they have a singular Ig domain, hydrophobic transmembrane region and a highly basic cytoplasmic tail
Binds MHC I and interacts with B2 microglobins