HEMCAM, an adhesion molecule expressed by c-kit+ hemopoietic progenitors.
We have characterized the adhesion molecule HEMCAM, which is expressed by hemopoietic progenitors of embryonic bone marrow. HEMCAM belongs to the immunoglobulin superfamily and consists of the V-V-C2-C2-C2 Ig domains. There are three mRNA splice variants. One has a short cytoplasmic tail; another has a long tail; while the third seems to lack transmembrane and cytoplasmic regions. Except for the NH2-terminal sequence, HEMCAM is identical to gicerin, a molecular involved in neurite outgrowth and Wilm's kidney tumor progression in the chicken and it is significantly homologous with MUC18 a molecule involved in melanoma progression and metastasis in human beings. In the bone marrow the HEMCAM+ cell population contains c-kit+ subsets. HEMCAM+ cells coexpressing the receptor tyrosine kinase c-kit give rise to T cells at a frequency of 0.17 when injected intrathymically in congenic animals. As HEMCAM+, c-kit+ cells differentiate into myeloid and erythroid CFU's the double-positive cell population seems to contain precursors for multiple lineages. HEMCAM promotes cell-cell adhesion of transfected cells. Cross-linking of murine HEMCAM leads to cell spreading of T-lymphocyte progenitors adhering to the vascular adhesion molecules, PECAM-1 and VCAM-1. Thus, HEMCAM is likely to be involved in cellular adhesion and homing processes.
Vainio
O
O
Basel Institute for Immunology, Switzerland.
Dunon
D
D
Aïssi
F
F
Dangy
J P
JP
McNagny
K M
KM
Imhof
B A
BA
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D030161:Avian Proteins; D014408:Biomarkers, Tumor; D001853:Bone Marrow / Q000378:metabolism; D001854:Bone Marrow Cells; D051929:CD146 Antigen; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D002454:Cell Differentiation; D002465:Cell Movement; D002645:Chickens; D003001:Cloning, Molecular; D004730:Endothelium, Vascular / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry; D008969:Molecular Sequence Data; D019006:Neural Cell Adhesion Molecules; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes / Q000166:cytology
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D030161:Avian Proteins; D014408:Biomarkers, Tumor; D051929:CD146 Antigen; D015815:Cell Adhesion Molecules; C497902:MCAM protein, human; D008562:Membrane Glycoproteins; D019006:Neural Cell Adhesion Molecules; D011994:Recombinant Proteins; D019009:Proto-Oncogene Proteins c-kit