PMID- 8080982
OWN - NLM
STAT- MEDLINE
DCOM- 19941012
LR  - 20210216
IS  - 0006-4971 (Print)
IS  - 0006-4971 (Linking)
VI  - 84
IP  - 6
DP  - 1994 Sep 15
TI  - Platelet alpha-granule and plasma membrane share two new components: CD9 and 
      PECAM-1.
PG  - 1722-30
AB  - CD9 (p24) and PECAM1 (CD31) antigens are well-defined components of the platelet 
      plasma membrane. Both are integral glycoproteins (GPs) implicated in the adhesive 
      and aggregative properties of human platelets. In the present report, we have 
      investigated their subcellular localization using immunoelectron microscopy. The 
      monospecificity of the two polyclonal antibodies used was confirmed by 
      immunoblotting. On normal resting platelets, immunolabeling for CD9 and PECAM1 
      was found lining the plasma membrane and the luminal face of the open canalicular 
      system. Some labeling was also consistently found on the alpha-granule limiting 
      membrane. This was confirmed by double labeling experiments in which fibrinogen 
      and von Willebrand factor (vWF) were used as alpha-granule markers. CD9 and 
      PECAM-1 were found lining the membrane of the same granules that contained 
      fibrinogen and vWF in their matrix. CD9 and PECAM-1 thus appear to have an 
      intracellular distribution identical to GPIIb-IIIa, a major aggregation platelet 
      receptor. To rule out a cross-reactivity of the two polyclonal antibodies with 
      GPIIb/IIIa, we studied PECAM1 and CD9 expression on the platelets from a patient 
      with type I Glanzmann's thrombasthenia whose platelets are devoid of GPIIb/IIIa. 
      The same pattern of labeling was observed for both antigens as for normal 
      platelets. Normal platelets were further observed after stimulation by agonists 
      that either fail to induce (ADP) or induce granule secretion (thrombin). After 
      treatment with ADP, platelets changed shape and centralized their granules; the 
      plasma membrane immunolabeling remained unchanged; and gold particles were still 
      found decorating the periphery of the centralized alpha-granules. After thrombin 
      treatment, alpha-granules fused with the platelet membrane and secretion 
      occurred. A significant increase of labeling was then observed on the platelet 
      surface. From these results we conclude that the alpha-granule membrane contains 
      two additional receptors in common with the plasma membrane. This suggests that 
      alpha-granule membrane receptors may originate from a dual mechanism: direct 
      targeting from the Golgi complex in megakaryocytes (for alpha-granule-specific 
      receptors such as P-selectin) or by endocytosis from the plasma membrane (for 
      proteins distributed in the two compartments).
FAU - Cramer, E M
AU  - Cramer EM
AD  - Inserm U.348, Hopital Lariboisiere, Paris, France.
FAU - Berger, G
AU  - Berger G
FAU - Berndt, M C
AU  - Berndt MC
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Blood
JT  - Blood
JID - 7603509
RN  - 0 (Antigens, CD)
RN  - 0 (Antigens, Differentiation, Myelomonocytic)
RN  - 0 (CD9 protein, human)
RN  - 0 (Cell Adhesion Molecules)
RN  - 0 (Membrane Glycoproteins)
RN  - 0 (Platelet Endothelial Cell Adhesion Molecule-1)
RN  - 0 (Platelet Membrane Glycoproteins)
RN  - 0 (Tetraspanin 29)
RN  - 61D2G4IYVH (Adenosine Diphosphate)
RN  - EC 3.4.21.5 (Thrombin)
SB  - IM
MH  - Adenosine Diphosphate/pharmacology
MH  - Antigens, CD/*blood
MH  - Antigens, Differentiation, Myelomonocytic/*blood
MH  - Blood Platelets/*immunology/ultrastructure
MH  - Cell Adhesion Molecules/*blood
MH  - Cell Membrane/*immunology
MH  - Cytoplasmic Granules/*immunology/ultrastructure
MH  - Humans
MH  - Intracellular Membranes/immunology
MH  - *Membrane Glycoproteins
MH  - Microscopy, Immunoelectron
MH  - Platelet Endothelial Cell Adhesion Molecule-1
MH  - Platelet Membrane Glycoproteins/analysis/immunology
MH  - Tetraspanin 29
MH  - Thrombasthenia/blood
MH  - Thrombin/pharmacology
EDAT- 1994/09/15 00:00
MHDA- 1994/09/15 00:01
CRDT- 1994/09/15 00:00
PHST- 1994/09/15 00:00 [pubmed]
PHST- 1994/09/15 00:01 [medline]
PHST- 1994/09/15 00:00 [entrez]
AID - S0006-4971(20)76971-5 [pii]
PST - ppublish
SO  - Blood. 1994 Sep 15;84(6):1722-30.