OLIGOMER FORMATION OF HISTAMINE-H2-RECEPTORS EXPRESSED IN SF9 AND COS7 CELLS

A histamine H2 receptor, which had been mutated at its glycosylation s ite and tagged at its N-terminus with an HA tag (HA-H2 receptor), was expressed in Sf9 cells and COS7 cells. Immunoprecipitation and immunob lotting of HA-H2 receptors with alpha HA antibody revealed four bands of 31.5 +/- 2.5 kDa, 59.0 +/- 6.0 kDa, 80.5 +/- 4.5 kDa and 120 kDa. T hese bands were also detected by immunoblot using anti-H2 receptor ser um (C-terminus), In addition, H2 receptors without the HA-tag co-immun oprecipitated with HA-tagged H2 receptors devoid of the 51 C-terminal amino acids, via immunoprecipitation with alpha HA antibody, when the two receptors were coexpressed, These results suggest that H2 receptor s are present as receptor oligomers and that the C-terminal portion is not involved in the formation of these oligomers. (C) 1997 Federation of European Biochemical Societies.