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Cold‐shock induction of a family of TIP1‐related proteins associated with the membrane in Saccharomyces cerevisiae
Author(s) -
Kowalski Leslie R. Z.,
Kondo Keiji,
Inouye Masayori
Publication year - 1995
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1995.tb02248.x
Subject(s) - biology , saccharomyces cerevisiae , biochemistry , serine , cold shock domain , membrane protein , homology (biology) , genetics , yeast , gene , membrane , rna , enzyme
Summary TIP1 is the first known cold‐shock‐and heat‐shock‐induced gene in Saccharomyces cerevisiae. Here it is demonstrated that a TIP1 homologue, TIR1 , which had been previously cloned as SRP1 (serine‐rich protein), is strongly induced by a downshift in growth temperature from 30 to 10°C. We further cloned TIR2 , which is transcribed at a low basal level but is increased strongly by cold shock and, to a lesser extent, by heat shock. The predicted protein sequence of TIR2 demonstrates remarkable homology to T1R1 (72.2%) and is also homologous with TIP1 (49%). TIP1, TIR1 and TIR2 are rich in both serine and alanine residues and each contains serine‐rich tandem repeats. The proteins contain putative N ‐terminal signal peptides as well as hydro‐phobic C ‐terminal sequences, indicating that the proteins may be membrane bound. The predicted protein sequences are also consistent with extensive O ‐mannosylation as well as glycosyl‐phosphatidyl inositol (GPI) membrane anchoring. Cell fractionation analysis as well as studies using a yeast strain that is conditionally deficient in glycosylation demonstrate that TIP1 is a heavily modified membrane‐associated protein. Single, double combinations and triple mutants were created and none demonstrated any obvious phenotype, indicating that this family of genes is not essential for normal growth.