scholarly journals A late Golgi sorting function for Saccharomyces cerevisiae Apm1p, but not for Apm2p, a second yeast clathrin AP medium chain-related protein.

1995 ◽  
Vol 6 (1) ◽  
pp. 41-58 ◽  
Author(s):  
J D Stepp ◽  
A Pellicena-Palle ◽  
S Hamilton ◽  
T Kirchhausen ◽  
S K Lemmon
Keyword(s):  
Molecular Weight ◽  
Heavy Chain ◽  
Chain Gene ◽  
Temperature Sensitive ◽  
Related Protein ◽  
Heavy Chain Gene ◽  
Medium Chain ◽  
Clathrin Heavy Chain ◽  
Sensitive Allele ◽  
Yeast Genes

Mammalian clathrin-associated protein (AP) complexes, AP-1 (trans-Golgi network) and AP-2 (plasma membrane), are composed of two large subunits of 91-107 kDa, one medium chain (mu) of 47-50 kDa and one small chain (sigma) of 17-19 kDa. Two yeast genes, APM1 and APM2, have been identified that encode proteins related to AP mu chains. APM1, whose sequence was reported previously, codes for a protein of 54 kDa that has greatest similarity to the mammalian 47-kDa mu 1 chain of AP-1. APM2 encodes an AP medium chain-related protein of 605 amino acids (predicted molecular weight of 70 kDa) that is only 30-33% identical to the other family members. In yeast containing a normal clathrin heavy chain gene (CHC1), disruptions of the APM genes, singly or in combination, had no detectable phenotypic consequences. However, deletion of APM1 greatly enhanced the temperature-sensitive growth phenotype and the alpha-factor processing defect displayed by cells carrying a temperature-sensitive allele of the clathrin heavy chain gene. In contrast, deletion of APM2 caused no synthetic phenotypes with clathrin mutants. Biochemical analysis indicated that Apm1p and Apm2p are components of distinct high molecular weight complexes. Apm1p, Apm2p, and clathrin cofractionated in a discrete vesicle population, and the association of Apm1p with the vesicles was disrupted in CHC1 deletion strains. These results suggest that Apm1p is a component of an AP-1-like complex that participates with clathrin in sorting at the trans-Golgi in yeast. We propose that Apm2p represents a new class of AP-medium chain-related proteins that may be involved in a nonclathrin-mediated vesicular transport process in eukaryotic cells.

scholarly journals Sequence of the clathrin heavy chain from Saccharomyces cerevisiae and requirement of the COOH terminus for clathrin function.

1991 ◽  
Vol 112 (1) ◽  
pp. 65-80 ◽  
Author(s):  
S K Lemmon ◽  
A Pellicena-Palle ◽  
K Conley ◽  
C L Freund
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Heavy Chain ◽  
Coiled Coil ◽  
Coated Vesicle ◽  
Chain Gene ◽  
Temperature Sensitive ◽  
Clathrin Heavy Chain ◽  
And Function ◽  
Major Defect

The sequence of the clathrin heavy chain gene, CHC1, from Saccharomyces cerevisiae is reported. The gene encodes a protein of 1,653 amino acids that is 50% identical to the rat clathrin heavy chain (HC) (Kirchhausen, T., S. C. Harrison, E. P. Chow, R. J. Mattaliano, R. L. Ramachandran, J. Smart, and J. Brosius. 1987. Proc. Natl. Acad. Sci. USA. 84:8805-8809). The alignment extends over the complete length of the two proteins, except for a COOH-terminal extension of the rat HC and a few small gaps, primarily in the globular terminal domain. The yeast HC has four prolines in the region of the rat polypeptide that was proposed to form the binding site for clathrin light chains via an alpha-helical coiled-coil interaction. The yeast protein also lacks the COOH-terminal Pro-Gly rich segment present in the last 45 residues of the rat HC, which were proposed to be involved in the noncovalent association of HCs to form trimers at the triskelion vertex. To examine the importance of the COOH terminus of the HC for clathrin function, a HC containing a COOH-terminal deletion of 57 amino acids (HC delta 57) was expressed in clathrin-deficient yeast (chc1-delta). HC delta 57 rescued some of the phenotypes (slow growth at 30 degrees, genetic instability, and defects in mating and sporulation) associated with the chc1-delta mutation to normal or near normal. Also, truncated HCs were assembled into triskelions. However, cells with HC delta 57 were temperature sensitive for growth and still displayed a major defect in processing of the mating pheromone alpha-factor. Fewer coated vesicles could be isolated from cells with HC delta 57 than cells with the wild-type HC. This suggests that the COOH-terminal region is not required for formation of trimers, but it may be important for normal clathrin-coated vesicle structure and function.

scholarly journals Fusion of the ALK Gene to the Clathrin Heavy Chain Gene, CLTC, in Inflammatory Myofibroblastic Tumor

2001 ◽  
Vol 159 (2) ◽  
pp. 411-415 ◽  
Author(s):  
Julia A. Bridge ◽  
Masahiko Kanamori ◽  
Zhigui Ma ◽  
Diane Pickering ◽  
D. Ashley Hill ◽  
...  
Keyword(s):  
Heavy Chain ◽  
Inflammatory Myofibroblastic Tumor ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Clathrin Heavy Chain

scholarly journals SCD5, a suppressor of clathrin deficiency, encodes a novel protein with a late secretory function in yeast.

1996 ◽  
Vol 7 (2) ◽  
pp. 245-260 ◽  
Author(s):  
K K Nelson ◽  
M Holmer ◽  
S K Lemmon
Keyword(s):  
Heavy Chain ◽  
Secretory Pathway ◽  
Vesicular Transport ◽  
Carboxypeptidase Y ◽  
Chain Gene ◽  
Temperature Sensitive ◽  
Coat Proteins ◽  
Clathrin Heavy Chain ◽  
Biochemical Analyses ◽  
Novel Protein

Clathrin and its associated proteins constitute a major class of coat proteins involved in vesicle budding during membrane transport. An interesting characteristic of the yeast clathrin heavy chain gene (CHC1) is that in some strains a CHC1 deletion is lethal, while in others it is not. Recently, our laboratory developed a screen that identified five multicopy suppressors that can rescue lethal strains of clathrin heavy chain-deficient yeast (Chc - scd1-i) to viability. One of these suppressors, SCD5, encodes a novel protein of 872 amino acids containing two regions of repeated motifs of unknown function. Deletion of SCD5 has shown that it is essential for cell growth at 30 degrees C. scd5-delta strains carrying low copy plasmids encoding C-terminal truncations of Scd5p are temperature sensitive for growth at 37 degrees C. At the nonpermissive temperature, cells expressing a 338-amino acid deletion (Scd5P-delta 338) accumulate an internal pool of fully glycosylated invertase and mature alpha-factor, while processing and sorting of the vacuolar hydrolase carboxypeptidase Y is normal. The truncation mutant also accumulates 80- to 100-nm vesicles similar to many late sec mutants. Moreover, at 34 degrees C, overexpression of Scd5p suppresses the temperature sensitivity of a sec2 mutant, which is blocked at a post-Golgi step of the secretory pathway. Biochemical analyses indicate that approximately 50% of Scd5p sediments with a 100,000 x g membrane fraction and is associated as a peripheral membrane protein. Overall, these results indicate that Scd5p is involved in vesicular transport at a late stage of the secretory pathway. Furthermore, this suggests that the lethality of clathrin-deficient yeast can be rescued by modulation of vesicular transport at this late secretory step.

scholarly journals Genetic instability of clathrin-deficient strains of Saccharomyces cerevisiae.

Genetics ◽  
1990 ◽  
Vol 124 (1) ◽  
pp. 27-38
Author(s):  
S K Lemmon ◽  
C Freund ◽  
K Conley ◽  
E W Jones
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heavy Chain ◽  
Copy Number ◽  
Genetic Background ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Genome Copy ◽  
Clathrin Heavy Chain ◽  
Genome Copy Number ◽  
Genome Content

Abstract Saccharomyces cerevisiae strains carrying a mutation in the clathrin heavy chain gene (CHC1) are genetically unstable and give rise to heterogeneous populations of cells. Manifestations of the instability include increases in genome copy number as well as compensatory genetic changes that allow better growing clathrin-deficient cells to take over the population. Increases in genome copy number appear to result from changes in ploidy as well as alterations in normal nuclear number. Genetic background influences the frequency at which cells with increased genome content are observed in different Chc- strains. We cannot distinguish whether genetic background affects the rate at which aberrant nuclear division events occur or a growth advantage of cells with increased nuclear and/or genome content. However, survival of chc1-delta cells does not require an increase in genome copy number. The clathrin heavy chain gene was mapped 1-2 cM distal to KEX1 on the left arm of chromosome VII by making use of integrated 2 mu plasmid sequences to destabilize distal chromosome segments and allow ordering of the genes.

Cloning and Characterization of a Novel Human Clathrin Heavy Chain Gene (CLTCL)

Genomics ◽  
1996 ◽  
Vol 35 (3) ◽  
pp. 466-472 ◽  
Author(s):  
Kimberly R. Long ◽  
James A. Trofatter ◽  
Vijaya Ramesh ◽  
Mary Kay McCormick ◽  
Alan J. Buckler
Keyword(s):  
Heavy Chain ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Clathrin Heavy Chain

scholarly journals Alternative splicing of clathrin heavy chain contributes to the switch from coated pits to plaques

2020 ◽  
Vol 219 (9) ◽  
Author(s):  
Gilles Moulay ◽  
Jeanne Lainé ◽  
Mégane Lemaître ◽  
Masayuki Nakamori ◽  
Ichizo Nishino ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Alternative Splicing ◽  
Genetic Control ◽  
Heavy Chain ◽  
Muscle Development ◽  
Tissue Homeostasis ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Coated Pits ◽  
Clathrin Heavy Chain

Clathrin function directly derives from its coat structure, and while endocytosis is mediated by clathrin-coated pits, large plaques contribute to cell adhesion. Here, we show that the alternative splicing of a single exon of the clathrin heavy chain gene (CLTC exon 31) helps determine the clathrin coat organization. Direct genetic control was demonstrated by forced CLTC exon 31 skipping in muscle cells that reverses the plasma membrane content from clathrin plaques to pits and by promoting exon inclusion that stimulated flat plaque assembly. Interestingly, mis-splicing of CLTC exon 31 found in the severe congenital form of myotonic dystrophy was associated with reduced plaques in patient myotubes. Moreover, forced exclusion of this exon in WT mice muscle induced structural disorganization and reduced force, highlighting the contribution of this splicing event for the maintenance of tissue homeostasis. This genetic control on clathrin assembly should influence the way we consider how plasticity in clathrin-coated structures is involved in muscle development and maintenance.

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