Biomedical subjects

M Goebl

Publications and source records attributed to M Goebl.

30 records · Page 2Linked to original sources

PubMed1991

Yeast CAL1 is a structural and functional homologue to the DPR1 (RAM) gene involved in ras processing.

A 2.3-kilobase pair DNA fragment of the yeast CAL1 gene was cloned by complementation of the cal1-1 mutation, which causes a defect in nuclear division and bud formation (Ohya, Y., Ohsumi, Y., and Anraku, Y. (1984) Mol. & Gen. Genet. 193, 389-394). Nucleotide sequencing of this fragment revealed a single open reading frame (ORF) encoding a polypeptide of 376 amino acids. Comparative analysis of the predicted amino acid sequence has shown that the CAL1 product has similarity to two yeast proteins: the DPR1 (RAM) gene product that is involved in processing of ras protein at the farnesylation step, and the essential ORF2 protein whose structural gene has a head-to-head arrangement with PRP4, which is involved in mRNA processing. Functional homology between CAL1 and DPR1 has also been suggested from genetic evidence that multiple copies of the CAL1 gene suppress the growth defects of a dpr1 null mutant at high temperature. This suppression is Ca(2+)-dependent, since it was not observed in complete medium containing 200 microM CaCl2 but was apparent in medium containing 100 mM CaCl2. From sequence analysis of the cal1-1 mutation, together with the alignment of the three gene products, we have concluded that the conserved Gly328 in the C terminus is important for activity. We suggest that the CAL1 protein participates in a ras-like C-terminal modification of proteins involved in nuclear division and bud growth.

Amino Acid Sequence↗

PubMed1991

Mutations in the CDP-choline pathway for phospholipid biosynthesis bypass the requirement for an essential phospholipid transfer protein.

SEC14p is the yeast phosphatidylinositol (PI)/phosphatidylcholine (PC) transfer protein, and it effects an essential stimulation of yeast Golgi secretory function. We now report that the SEC14p localizes to the yeast Golgi and that the SEC14p requirement can be specifically and efficiently bypassed by mutations in any one of at least six genes. One of these suppressor genes was the structural gene for yeast choline kinase (CKI), disruption of which rendered the cell independent of the normally essential SEC14p requirement. The antagonistic action of the CKI gene product on SEC14p function revealed a previously unsuspected influence of biosynthetic activities of the CDP-choline pathway for PC biosynthesis on yeast Golgi function and indicated that SEC14p controls the phospholipid content of yeast Golgi membranes in vivo.

Carrier Proteins↗

PubMed1991

The TPR snap helix: a novel protein repeat motif from mitosis to transcription.

The recently discovered TPR gene family encodes a diverse group of proteins that function in mitosis, transcription, splicing, protein import and neurogenesis. These multi-domain proteins all contain tandemly arranged repeats of a 34-amino acid motif that are presumed to form helix-turn structures, each with a 'knob' and 'hole', acting as helix-associating domains.

Amino Acid Sequence↗

PubMed1991

The yeast SRM1 protein and human RCC1 protein share analogous functions.

The Saccharomyces cerevisiae protein SRM1 and the mammalian protein RCC1 have amino acid sequence similarity throughout their lengths. SRM1 was defined by a recessive mutation in yeast that both activates the signal transduction pathway required for mating and leads to arrest in the G1 phase of the cell cycle. RCC1 was defined by a recessive mutation in hamster cells that causes premature chromosome condensation and other characteristics of entry into mitosis. Despite the seemingly different roles implied by these phenotypes, we suggest that RCC1 and SRM1 proteins have similar functions. In particular, we find that RCC1 can complement the temperature-sensitive growth phenotype of two independent srm1 mutations and also complements, at least partially, phenotypes associated with activation of the pheromone response pathway, such as transcription induction of FUS1. However, RCC1 fails to complement an srm1 null allele. Further characterization of the srm1 mutant phenotype reveals a defect in plasmid and chromosome stability, suggesting that the mutants have a defect in DNA replication, mitosis, or their coordination. Finally, like RCC1, SRM1 is a nuclear protein. Together, these data imply that SRM1 and RCC1 have a common role in their respective organisms.

Amino Acid Sequence↗

PubMed1991

N-myristoylation is required for function of the pheromone-responsive G alpha protein of yeast: conditional activation of the pheromone response by a temperature-sensitive N-myristoyl transferase.

In a screen designed to identify novel mutations in the mating response pathway of Saccharomyces cerevisiae, we isolated conditional alleles of NMT1, the gene encoding N-myristoyl transferase. Genetic data indicate that Nmt1 deficiency results in the activation of the pheromone response at the level of Gpa1, the alpha subunit of the pheromone-responsive G protein. We show that Gpa1 is myristoylated by Nmt1, and without this normally stable modification, Gpa1 is unable to inhibit pheromone signaling. This loss of Gpa1 function is probably not the result of improper subcellular localization. Unlike the mammalian G alpha i proteins alpha i and alpha o, nonmyristoylated Gpa1 is able to associate with membranes. In addition to Gpa1, our data indicate that Nmt1 myristoylates other proteins essential to vegetative growth.

Acyltransferases↗

PubMed1991

CDC55, a Saccharomyces cerevisiae gene involved in cellular morphogenesis: identification, characterization, and homology to the B subunit of mammalian type 2A protein phosphatase.

Microscopic screening of a collection of cold-sensitive mutants of Saccharomyces cerevisiae led to the identification of a new gene, CDC55, which appears to be involved in the morphogenetic events of the cell cycle. CDC55 maps between CDC43 and CHC1 on the left arm of chromosome VII. At restrictive temperature, the original cdc55 mutant produces abnormally elongated buds and displays a delay or partial block of septation and/or cell separation. A cdc55 deletion mutant displays a cold-sensitive phenotype like that of the original isolate. Sequencing of CDC55 revealed that it encodes a protein of about 60 kDa, as confirmed by Western immunoblots using Cdc55p-specific antibodies. This protein has greater than 50% sequence identity to the B subunits of rabbit skeletal muscle type 2A protein phosphatase; the latter sequences were obtained by analysis of peptides derived from the purified protein, a polymerase chain reaction product, and cDNA clones. An extragenic suppressor of the cdc55 mutation lies in BEM2, a gene previously identified on the basis of an apparent role in bud emergence.

Amino Acid Sequence↗

PubMed1991

The fission yeast dis3+ gene encodes a 110-kDa essential protein implicated in mitotic control.

The fission yeast mutant dis3-54 is defective in mitosis and fails in chromosome disjunction. Its phenotype is similar to that of dis2-11, a mutant with a mutation in the type 1 protein phosphatase gene. We cloned the dis3+ gene by transformation. Nucleotide sequencing predicts a coding region of 970 amino acids interrupted by a 164-bp intron at the 65th codon. The predicted dis3+ protein shares a weak but significant similarity with the budding yeast SSD1 or SRK1 gene product, the gene for which is a suppressor for the absence of a protein phosphatase SIT4 gene or the BCY1 regulatory subunit of cyclic AMP-dependent protein kinase. Anti-dis3 antibodies recognized the 110-kDa dis3+ gene product, which is part of a 250- to 350-kDa oligomer and is enriched in the nucleus. The cellular localization of the dis3+ protein is reminiscent of that of the dis2+ protein, but these two proteins do not form a complex. A type 1 protein phosphatase activity in the dis3-54 mutant extracts is apparently not affected. The dis3+ gene is essential for growth; gene disruptant cells do not germinate and fail in cell division. Increased dis3+ gene dosage reverses the Ts+ phenotype of a cdc25 wee1 strain, as does increased type 1 protein phosphatase gene dosage. Double mutant dis3 dis2 is lethal even at the permissive temperature, suggesting that the dis2+ and dis3+ genes may be functionally overlapped. The role of the dis3+ gene product in mitosis is unknown, but this gene product may be directly or indirectly involved in the regulation of mitosis.

Amino Acid Sequence↗

PubMed1991

Molecular cloning of the human gene, CCG2, that complements the BHK-derived temperature-sensitive cell cycle mutant tsBN63: identity of CCG2 with the human X chromosomal SCAR/RPS4X gene.

A temperature-sensitive mutant tsBN63 cell line was isolated by the fluorodeoxyuridine method from the BHK21/13 cell line after mutagenesis with nitrosoguanidine. When cultures of tsBN63 cells growing asynchronously at 33.5 degrees C were shifted to 39.5 degrees C, a nonpermissive temperature, the ability for protein synthesis was rapidly reduced and cell proliferation stopped mainly at G1 phase, and partly at G2 phase. Synchronized cultures of tsBN63 cells did not commence DNA synthesis when shifted up in G1 phase. The human gene complementing the tsBN63 mutation was cloned by DNA-mediated gene transfer and its cDNA of 1.1 kb conferring ts+ phenotype on tsBN63 cells was isolated from the cDNA library of Raj (mer+) cells with a frequency of 10(-3). On the basis of the determined nucleotide sequence, the isolated human gene turned out to be the X chromosomal RPS4X encoding the ribosomal protein S4. The size of the CCG2 gene was estimated to be about 12 kb by complementation analysis of the tsBN63 mutation with cloned genomic DNA.

Amino Acid Sequence↗

PubMed1990

Protein splicing converts the yeast TFP1 gene product to the 69-kD subunit of the vacuolar H(+)-adenosine triphosphatase.

The TFP1 gene of the yeast Saccharomyces cerevisiae encodes two proteins: the 69-kilodalton (kD) catalytic subunit of the vacuolar proton-translocating adenosine triphosphatase (H(+)-ATPase) and a 50-kD protein. The 69-kD subunit is encoded by the 5' and 3' thirds of the TFP1 coding region, whereas the 50-kD protein is encoded by the central third. Evidence is presented that both the 69-kD and 50-kD proteins are obtained from a single translation product that is cleaved to release the 50-kD protein and spliced to form the 69-kD subunit.

Animals↗

PubMed1990

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Amino Acid Sequence↗

PubMed1990

A repeating amino acid motif in CDC23 defines a family of proteins and a new relationship among genes required for mitosis and RNA synthesis.

We have identified and characterized a novel, repeating 34 amino acid motif (the TPR motif) that is reiterated several times within the CDC23 gene product of S. cerevisiae. Multiple copies of this motif were discovered in five other proteins, three encoded by cell division cycle genes required to complete mitosis and two involved in RNA synthesis. Quantitative sequence analyses suggest the existence of a common underlying structure in each TPR unit that consists of amphipathic alpha-helical regions punctuated by proline-induced turns. The TPR motif defines a new family of genes and an important structural unit common to several proteins whose functions are required for mitosis and RNA synthesis.

Amino Acid Sequence↗

PubMed1988

CDC33 encodes mRNA cap-binding protein eIF-4E of Saccharomyces cerevisiae.

The bcy1 mutation makes the cdc33 start mutant arrest at random points in the cell cycle instead of only at G1. We cloned and sequenced CDC33. This coding sequence is identical to that of the gene encoding the Saccharomyces cerevisiae 24-kilodalton mRNA cap-binding protein, eIF-4E.

Amino Acid Sequence↗