Functional role of lipid rafts in CD20 activity?
CD20 is a B-lymphocyte-specific integral membrane protein, implicated in the regulation of transmembrane calcium conductance, cell-cycle progression and B-lymphocyte proliferation. CD20 is proposed to function as a SOCC (store-operated calcium channel). SOCCs are activated by receptor-stimulated calcium depletion of intracellular stores. Sustained calcium conductivity across the plasma membrane mediated by SOCC activity is required for long-term calcium-dependent processes, such as transcriptional control and gene expression. Cross-linking of CD20 by antibodies (e.g. Rituxan) has been reported to induce a rapid redistribution of CD20 into specialized microdomains at the plasma membrane, known as lipid rafts. Recruitment of CD20 into lipid rafts and its homo-oligomerization are suggested to be crucial for CD20 activity and regulation. This review outlines recent biochemical studies characterizing the role of CD20 in calcium signalling in B-lymphocytes and evaluates an engagement of lipid rafts in the regulation of CD20-mediated calcium conductivity.
Janas
Eva
E
Rheumatoid Arthritis Biology, RI-CEDD, Medicines Research Centre, GlaxoSmithKline, Gunnel's Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K. eva.x.janas@gsk.com
Priest
Richard
R
Malhotra
Rajneesh
R
D018951:Antigens, CD20 / Q000737:chemistry / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling; D006801:Humans; D066298:In Vitro Techniques; D021962:Membrane Microdomains / Q000276:immunology* / Q000378:metabolism*; D008954:Models, Biological; D008958:Models, Molecular; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism
D018951:Antigens, CD20; D015220:Calcium Channels; D011947:Receptors, Antigen, B-Cell