A proline‐rich protein, verprolin, involved in cytoskeletal organization and cellular growth in the yeast Saccharomyces cerevisiae

Abstract

A gene (VRP1) encoding a novel proline-rich protein (verprolin) has been isolated from the yeast Saccharomyces cerevisiae as a result of its hybridization to a chick vinculin cDNA probe. The deduced protein sequence contains 24% proline residues present as proline-rich motifs throughout the verprolin sequence. Several of these motifs resemble recently identified sequences shown to bind Src homology 3 (SH3) domains in vitro. Replacement of the wild-type VRP1 allele with a mutant allele results in strains that grow slower than wild-type strains and are temperature sensitive. The vrp1 mutants are impaired in both cell shape and size and display aberrant chitin and actin localization. We propose that verporlin is involved in the maintenance of the yeast actin cytoskeleton, through interactions with other proteins, possibly containing SH3 domains.

Mutations Altering the Mitochondrial-Cytoplasmic Distribution of Mod5p Implicate the Actin Cytoskeleton and mRNA 3′ Ends and/or Protein Synthesis in Mitochondrial Delivery

“…6 and 7). It was found to be a very close match to the yeast VRP1 gene (19). The MDP2 sequence differs from VRP1 in six nucleotide positions and extends about 500 bp further in the 3Ј direction.…”

“…7). This consensus sequence resembles the peptide sequence for SH3 domain ligands (19,24,60). Interestingly, PAN1 is also somewhat proline rich (8.1%) and possesses proline-containing motifs such as PXP (where X is I, V, or T) and PXQP (where X is T or V).…”

“…A recent entry of the S. cerevisiae genome sequence effort (GenBank accession number U19028) verifies our DNA sequence. We believe that, despite the differences in DNA sequence, MDP2 and VRP1 are the same gene since disruption of VRP1 causes similar distortions of the actin cytoskeleton as do mdp2-1 and mdp2::LEU2 mutations (19). Hereafter, MDP2 will be referred to as MDP2/VRP1.…”

BED1, a gene encoding a galactosyltransferase homologue, is required for polarized growth and efficient bud emergence in Saccharomyces cerevisiae.

“…Eight mutations belonging to six complementation groups were isolated from the screening of 25,000 mutagenized colonies (see Materials and Methods for more detailed description of the screening procedure). The first mutation that we characterized was a mutated allele of the previously described VRP1 gene (Donnelly et al, 1993). This gene encodes verprolin, a proline-rich protein required for proper actin organization.…”

Verprolin: A cool set of actin‐binding sites and some very HOT prolines

“…The vrp1D cells are temperature-sensitive, that is, they are viable at 24 8C, but not at elevated temperature (e.g., 37 8C). In contrast, wild-type (VRP1) yeast cells are viable at both temperatures (2)(3)(4). The majority of vrp1D cells remain viable for a few hours and continue to grow in size at 37 8C but are unable to divide (5).…”