Cloning and preliminary characterization of a 121 kDa protein with multiple predicted C2 domains

In the course of characterizing proteins present in a preparation of vesicl es from rat adipocytes containing glucose transporters, we examined a prote in that migrated at 115 kDa upon SDS gel electrophoresis (designated vp115) . Sequences of tryptic peptides were obtained, and from this information th e cDNA for rat vp115 was cloned. The cDNA encodes an open reading frame for a protein of 121 kDa. Computer-aided sequence analysis predicted that vp11 5 has a potential membrane-inserted or membrane-spanning domain toward its amino terminus, followed by five C2 domains. Immunoblotting revealed that v p115 was not actually a component of the glucose transporter-containing ves icles, was most abundant in the plasma membranes and high density microsome fractions of rat adipocytes, and was expressed in all the major rat tissue s. (C) 1999 Elsevier Science B.V. All rights reserved.