Tmp21 and p24A, Two Type I Proteins Enriched in Pancreatic Microsomal Membranes, Are Members of a Protein Family Involved in Vesicular Trafficking

Blum, Robert; Feick, Peter; Puype, Magda; Vandekerckhove, Joël; Klengel, Rolf; Nastainczyk, Wolfgang; Schulz, Irene

doi:10.1074/jbc.271.29.17183

Cited by 99 publications

(97 citation statements)

References 34 publications

(36 reference statements)

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“…2A). TMP21 (also known as p23) is a member of the p24 cargo-protein family (47), and it is involved in protein transport and quality control in the ER and Golgi (48). TMP21 was identified as a GSAP (16,17,19) and is a negative modulator for A␤ production (16,49,50) via ␥-secretase activity (16) and/or altered APP trafficking (49,50).…”

Section: Discussionmentioning

confidence: 99%

Identification of Novel γ-Secretase-associated Proteins in Detergent-resistant Membranes from Brain

Hur

Teranishi²,

Kihara³

et al. 2012

Journal of Biological Chemistry

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Background:In AD, APP can be processed in lipid rafts, and ␥-secretase-associated proteins (GSAPs) can affect A␤ production. Results: We identify novel GSAPs in detergent-resistant membranes (DRMs). Conclusion: VDAC1 and CNTNAP1 associate with ␥-secretase in DRMs and affect APP processing with less effect on Notch processing. Significance: Novel GSAPs that regulate A␤ production can be used as AD therapeutic targets.

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Section: Discussionmentioning

confidence: 99%

Identification of Novel γ-Secretase-associated Proteins in Detergent-resistant Membranes from Brain

Hur

Teranishi²,

Kihara³

et al. 2012

Journal of Biological Chemistry

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“…Recently, a family of small and abundant type I integral membrane proteins, termed p24, was discovered (Wada et al, 1991;Schimmö ller et al, 1995;Stamnes et al, 1995;Belden and Barlowe, 1996;Blum et al, 1996;Sohn et al, 1996;Gayle et al, 1996;Rojo et al, 1997;Dominguez et al, 1998). This family is of unknown function, although at least some evidence argues that they play important roles in transport (Schimmö ller et al, 1995;Belden and Barlowe, 1996;Rojo et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Localization and Recycling of gp27 (hp24γ₃): Complex Formation with Other p24 Family Members

Füllekrug

Suganuma

Tang

et al. 1999

MBoC

130

178

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We report here the characterization of gp27 (hp24␥ 3 ), a glycoprotein of the p24 family of small and abundant transmembrane proteins of the secretory pathway. Immunoelectron and confocal scanning microscopy show that at steady state, gp27 localizes to the cis side of the Golgi apparatus. In addition, some gp27 was detected in COPI-and COPII-coated structures throughout the cytoplasm. This indicated cycling that was confirmed in three ways. First, 15°C temperature treatment resulted in accumulation of gp27 in pre-Golgi structures colocalizing with anterograde cargo. Second, treatment with brefeldin A caused gp27 to relocate into peripheral structures positive for both KDEL receptor and COPII. Third, microinjection of a dominant negative mutant of Sar1p trapped gp27 in the endoplasmic reticulum (ER) by blocking ER export. Together, this shows that gp27 cycles extensively in the early secretory pathway. Immunoprecipitation and coexpression studies further revealed that a significant fraction of gp27 existed in a hetero-oligomeric complex. Three members of the p24 family, GMP25 (hp24␣ 2 ), p24 (hp24␤ 1 ), and p23 (hp24␦ 1 ), coprecipitated in what appeared to be stochiometric amounts. This heterocomplex was specific. Immunoprecipitation of p26 (hp24␥ 4 ) failed to coprecipitate GMP25, p24, or p23. Also, very little p26 was found coprecipitating with gp27. A functional requirement for complex formation was suggested at the level of ER export. Transiently expressed gp27 failed to leave the ER unless other p24 family proteins were coexpressed. Comparison of attached oligosaccharides showed that gp27 and GMP25 recycled differentially. Only a very minor portion of GMP25 displayed complex oligosaccharides. In contrast, all of gp27 showed modifications by medial and trans enzymes at steady state. We conclude from these data that a portion of gp27 exists as hetero-oligomeric complexes with GMP25, p24, and p23 and that these complexes are in dynamic equilibrium with individual p24 proteins to allow for differential recycling and distributions.

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“…Among these are CHOp24 and p23, which are enriched in COP I-coated vesicles isolated from mammalian cells (Blum et al, 1996;Sohn et al, 1996;Stamnes et al, 1995). Both CHOp24 and p23 have double-lysine and double-phenylalanine signals that can directly bind to COP I coatomer and have been suggested to be actively packaged into COP I-coated vesicles Sohn et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Identification of Potential Regulatory Elements for the Transport of Emp24p

Nakamura

Yamazaki

Sato

et al. 1998

MBoC

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To examine the possibility of active recycling of Emp24p between the endoplasmic reticulum (ER) and the Golgi, we sought to identify transport signal(s) in the carboxylterminal region of Emp24p. Reporter molecules were constructed by replacing parts of a control invertase-Wbp1p chimera with those of Emp24p, and their transport rates were assessed. The transport of the reporter was found to be accelerated by the presence of the cytoplasmic domain of Emp24p. Mutational analyses revealed that the two carboxylterminal residues, leucine and valine (LV), were necessary and sufficient to accelerate the transport. The acceleration was sequence specific, and the terminal valine appeared to be more important. The LV residues accelerated not only the overall transport to the vacuole but also the ER to cis-Golgi transport, suggesting its function in the ER export. Hence the LV residues are a novel anterograde transport signal. The double-phenylalanine residues did not affect the transport by itself but attenuated the effect of the anterograde transport signal. On the other hand, the transmembrane domain significantly slowed down the ER to cis-Golgi transport and effectively counteracted the anterograde transport signal at this step. It may also take part in the retrieval of the protein, because the overall transport to the vacuole was more evidently slowed down. Consistently, the mutation of a conserved glutamine residue in the transmembrane domain further slowed down the transport in a step after arriving at the cis-Golgi. Taken together, the existence of the anterograde transport signal and the elements that regulate its function support the active recycling of Emp24p.

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Tmp21 and p24A, Two Type I Proteins Enriched in Pancreatic Microsomal Membranes, Are Members of a Protein Family Involved in Vesicular Trafficking

Cited by 99 publications

References 34 publications

Identification of Novel γ-Secretase-associated Proteins in Detergent-resistant Membranes from Brain

Identification of Novel γ-Secretase-associated Proteins in Detergent-resistant Membranes from Brain

Localization and Recycling of gp27 (hp24γ₃): Complex Formation with Other p24 Family Members

Identification of Potential Regulatory Elements for the Transport of Emp24p

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Tmp21 and p24A, Two Type I Proteins Enriched in Pancreatic Microsomal Membranes, Are Members of a Protein Family Involved in Vesicular Trafficking

Cited by 99 publications

References 34 publications

Identification of Novel γ-Secretase-associated Proteins in Detergent-resistant Membranes from Brain

Identification of Novel γ-Secretase-associated Proteins in Detergent-resistant Membranes from Brain

Localization and Recycling of gp27 (hp24γ3): Complex Formation with Other p24 Family Members

Identification of Potential Regulatory Elements for the Transport of Emp24p

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Localization and Recycling of gp27 (hp24γ₃): Complex Formation with Other p24 Family Members