Abstract
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 (μ) of 47-50 kDa and one small chain (σ) of 17-19 kDa. Two yeast genes, APM1 and APM2, have been identified that encode proteins related to AP μ chains. APM1, whose sequence was reported previously, codes for a protein of 54 kDa that has greatest similarity to the mammalian 47-kDa μ1 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 α-factor processing defect displayed by cells carrying a temperature-sensitive allele of the clathrin heavy chain gene. In contrast, deletion of APM1 caused no synthetic phenotypes with clathrin mutants. Biochemical analysis indicated that Apmlp and Apm2p are components of distinct high molecular weight complexes. Apmlp, Apm2p, and clathrin cofractionated in a discrete vesicle population, and the association of Apmlp with the vesicles was disrupted in CHC1 deletion strains. These results suggest that Apmlp 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.
| Original language | English |
|---|---|
| Pages (from-to) | 41-58 |
| Number of pages | 18 |
| Journal | Molecular Biology of the Cell |
| Volume | 6 |
| Issue number | 1 |
| State | Published - Jan 1 1995 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Cell Biology
- Genetics
- Molecular Biology
Cite this
A late golgi sorting function for Saccharomyces cerevisiae Apmlp, but not for Apm2p, a second yeast clathrin AP medium chain-related protein. / Stepp, J. David; Pellicena-Palle, Alexandra; Hamilton, Scott; Kirchhausen, Tomas; Lemmon, Sandra.
In: Molecular Biology of the Cell, Vol. 6, No. 1, 01.01.1995, p. 41-58.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A late golgi sorting function for Saccharomyces cerevisiae Apmlp, but not for Apm2p, a second yeast clathrin AP medium chain-related protein
AU - Stepp, J. David
AU - Pellicena-Palle, Alexandra
AU - Hamilton, Scott
AU - Kirchhausen, Tomas
AU - Lemmon, Sandra
PY - 1995/1/1
Y1 - 1995/1/1
N2 - 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 (μ) of 47-50 kDa and one small chain (σ) of 17-19 kDa. Two yeast genes, APM1 and APM2, have been identified that encode proteins related to AP μ chains. APM1, whose sequence was reported previously, codes for a protein of 54 kDa that has greatest similarity to the mammalian 47-kDa μ1 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 α-factor processing defect displayed by cells carrying a temperature-sensitive allele of the clathrin heavy chain gene. In contrast, deletion of APM1 caused no synthetic phenotypes with clathrin mutants. Biochemical analysis indicated that Apmlp and Apm2p are components of distinct high molecular weight complexes. Apmlp, Apm2p, and clathrin cofractionated in a discrete vesicle population, and the association of Apmlp with the vesicles was disrupted in CHC1 deletion strains. These results suggest that Apmlp 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.
AB - 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 (μ) of 47-50 kDa and one small chain (σ) of 17-19 kDa. Two yeast genes, APM1 and APM2, have been identified that encode proteins related to AP μ chains. APM1, whose sequence was reported previously, codes for a protein of 54 kDa that has greatest similarity to the mammalian 47-kDa μ1 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 α-factor processing defect displayed by cells carrying a temperature-sensitive allele of the clathrin heavy chain gene. In contrast, deletion of APM1 caused no synthetic phenotypes with clathrin mutants. Biochemical analysis indicated that Apmlp and Apm2p are components of distinct high molecular weight complexes. Apmlp, Apm2p, and clathrin cofractionated in a discrete vesicle population, and the association of Apmlp with the vesicles was disrupted in CHC1 deletion strains. These results suggest that Apmlp 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.
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M3 - Article
C2 - 7749194
AN - SCOPUS:0029010492
VL - 6
SP - 41
EP - 58
JO - Molecular Biology of the Cell
JF - Molecular Biology of the Cell
SN - 1059-1524
IS - 1
ER -