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Multiple serine phosphorylation sites on the 30 kDa TMV cell‐to‐cell movement protein synthesized in tobacco protoplasts
Author(s) -
Haley Ann,
Hunter Tony,
Kiberstis Paula,
Zimmern David
Publication year - 1995
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1995.08050715.x
Subject(s) - tobacco mosaic virus , phosphopeptide , movement protein , immunoprecipitation , protoplast , phosphorylation , peptide , phosphoserine , biology , kinase , biochemistry , tobamovirus , cell , polyacrylamide gel electrophoresis , n terminus , serine , microbiology and biotechnology , rna , virus , peptide sequence , virology , gene , coat protein , enzyme
p30, the protein required for cell‐to‐cell movement of tobacco mosaic virus (TMV), has a slightly reduced mobility on SDS‐polyacrylamide gels when isolated by immunoprecipitation from TMV‐infected protoplasts compared with that of p30 translated from viral RNA in vitro . Further investigation established a probable cause for the difference in mobility between the two: protoplasts incorporate [ 32 P]orthophosphate into p30 at multiple sites, predominantly as phosphoserine. Tryptic peptide mapping reveals at least five internal phosphopeptides in p30, besides the C‐terminal tryptic phosphopeptide already reported, involving at least two distinct domains of the protein (at residues 61–114 and residues 212–231), which may be substrates for different protein kinases. These structural results are consistent with a three‐domain model for the TMV movement protein with two regulatory domains similar to that recently proposed on genetic grounds for dianthovirus movement proteins.