Thrombin
By: Bailey Goodyear, Mike
Kiefer, Yami Hernandez
Location of thrombin production
• Prothrombin is produced in the: liver
• Prothrombin is then converted into thrombin.
• Thrombin is an enzyme not a hormone.
Function
• Thrombin converts fibrinogen into fibrin.
• Fibrin is the mesh-like material that aids in
blood clotting by forming a mesh that traps
red blood cells.
• Thrombin activation also leads to activation of
clotting factors, like Factor IV and platelets,
and immune response cells, like lymphocytes
and monocytes.
Pathway
Thrombin from the bloodstream binds to PARs
(Protease Activated Receptors) which function
as G-Protein Coupled Receptors, passing the
signal on using G-Proteins that begin a
Phosphorylation Cascade. The
Phosphorylation Cascade leads to a protein
called P13K. P13K activates two other
proteins that finally synthesize the activation
of four transcription factors.
Pathway Results
The transcription factors transcribe genes for:
• Cell growth/division
• Platelet aggregation and blood coagultion
• Angiogenesis, the formation of new blood
vessels from existing vessels
• Cell adhesion
Cellular Response
• Fibrinogen is converted into fibrin which forms
web-like structures that trap RBCs and
platelets, allowing clots to form. The clots
help the injury to heal and prevent foreign
pathogens or materials from entering the
wound.
Feedback
• Positive Feedback
• Thrombin activation results primarily in fibrin
production, but also begins a cascade of
activations of clotting factors like Factor V or
Factor VIII. The cascade forms a feedback
loop in which some of the proteins that are
activated then activate thrombin production.
Pathway Alteration
• Thrombophilia is abnormality that can result
in blood clots within blood vessels, also
known as thrombosis. Thrombosis can block
arteries, causing hypoxia, deprivation of
oxygen to cells, and the build up of lactic acid.
• It is caused by the Prothrombin G20210A
mutation, a point mutation, replacing guanine
with adenine, in a noncoding region of the
prothrombin gene.