Page 1872 - Williams Hematology ( PDFDrive )

1846 Part XII: Hemostasis and Thrombosis Chapter 112: Platelet Morphology, Biochemistry, and Function 1847

Platelet Con- Ratio
Known Platelet Plasma Concentration, centration,* Platelet/
Receptors Electron Microscopy Structure mcg/mL mcg/mL Plasma Sites of Synthesis
α β (GPIa/IIa; CD49b/ Tropocollagen = rodlike coil, 15 × – – – Fibroblasts
2 1
CD29; VLA-2) GPVI 3000; other forms have variable
GPIV (CD36)? degrees of fibril formation

GPIb (CD42b, c) Elliptical, nodular coil, length 10 34 3.4 Endothelial cells
α β (GPIIb/IIIa; CD41/ 5000, but with some 11,000 Å Megakaryocytes
IIb 3
CD61)

α β (GPIIb/IIIa; CD41/ Trinodular, asymmetrical; 475 Å 3000 7300 2.4 Hepatocytes
IIb 3
CD61) diameter
α β (CD51/CD61)
V 3

α β (GPIIb/IIIa; CD41/ 350 800 2.3 ?Hepatocytes
IIb 3
CD61)
α β (CD51/CD61)
V 3

α β (GPIc*/IIa (CD49e/ Extended antiparallel dimeric 300 315 1.1 Hepatocytes
5 1
CD29; VLA-5) structure Fibroblasts
α β (GPIIb/IIIa; CD41/ ?Endothelial cells
IIb 3
CD61) Megakaryocytes
Monocytes, etc.
GPIV (CD36) 3 Asymmetrical dumbbells, 0.16 4900 30,625 Megakaryocytes
α β (GPIIb/IIIa; CD41/ joined near smaller globular Many cultured
IIb 3
CD61)? domains cells
Integrin associated pro-
tein (CD47)

α β – – – Bone
V 3
?Other cells
α β (GPIc/IIa; CD49/ Cross-like structure – – – Fibroblasts
6 1
CD29; VLA-6) Many other cell
types

Unknown Unknown – – – Megakaryocytes
Endothelial cells

*Assumes 10 platelets per mL of packed platelets.
11
† DGEA, VTCG, and YIGSR are other amino acid sequences involved in function.

Kaushansky_chapter 112_p1829-1914.indd 1847 17/09/15 3:26 pm