Limits...
PIST regulates the intracellular trafficking and plasma membrane expression of cadherin 23.

Xu Z, Oshima K, Heller S - BMC Cell Biol. (2010)

Bottom Line: PIST, a Golgi-associated, PDZ domain-containing protein, interacted with cadherin 23 via the PDZ domain of PIST and the C-terminal PDZ domain-binding interface (PBI) of cadherin 23.PIST binds cadherin 23 via its PDZ domain and retains cadherin 23 in trans-Golgi network.MAGI-1 and harmonin can compete with PIST for binding cadherin 23 and release cadherin 23 from PIST's retention.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Otolaryngology--Head & Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA. xuzg@sdu.edu.cn

ABSTRACT

Background: The atypical cadherin protein cadherin 23 (CDH23) is crucial for proper function of retinal photoreceptors and inner ear hair cells. As we obtain more and more information about the specific roles of cadherin 23 in photoreceptors and hair cells, the regulatory mechanisms responsible for the transport of this protein to the plasma membrane are largely unknown.

Results: PIST, a Golgi-associated, PDZ domain-containing protein, interacted with cadherin 23 via the PDZ domain of PIST and the C-terminal PDZ domain-binding interface (PBI) of cadherin 23. By binding to cadherin 23, PIST retained cadherin 23 in the trans-Golgi network of cultured cells. The retention was released when either of the two known cadherin 23-binding proteins MAGI-1 and harmonin was co-expressed. Similar to MAGI-1 and harmonin, PIST was detected in mouse inner ear sensory hair cells.

Conclusions: PIST binds cadherin 23 via its PDZ domain and retains cadherin 23 in trans-Golgi network. MAGI-1 and harmonin can compete with PIST for binding cadherin 23 and release cadherin 23 from PIST's retention. Our finding suggests that PIST, MAGI-1 and harmonin collaborate in intracellular trafficking of cadherin 23 and regulate the plasma membrane expression of cadherin 23.

Show MeSH

Related in: MedlinePlus

MAGI-1 and harmonin release cadherin 23 from PIST's retention in transfected HEK293 cells. A. Myc-tagged cadherin 23 co-localizes with HA-tagged PIST at TGN-like structures. B. In the presence of EGFP-MAGI-1c, Myc-cadherin 23 colocalizes in the cytoplasm with EGFP-MAGI-1c, instead of co-localizing with HA-PIST at TGN-like structures. C. In the presence of EGFP-harmonin, Myc-cadherin 23(-68) co-localizes with EGFP-harmonin, instead of co-localizing with HA-PIST at TGN-like structures. D. In the presence of EGFP-harmonin, Myc-cadherin 23(+68) co-localizes with EGFP-harmonin, as well as with HA-PIST at TGN-like structures. Myc-cadherin 23 was stained with mouse anti-Myc antibody then TRITC-conjugated goat anti-mouse secondary antibody. HA-PIST was stained with rabbit anti-PIST antibody then Cy5-conjugated goat anti-rabbit secondary antibody. Scale bar, 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2967513&req=5

Figure 6: MAGI-1 and harmonin release cadherin 23 from PIST's retention in transfected HEK293 cells. A. Myc-tagged cadherin 23 co-localizes with HA-tagged PIST at TGN-like structures. B. In the presence of EGFP-MAGI-1c, Myc-cadherin 23 colocalizes in the cytoplasm with EGFP-MAGI-1c, instead of co-localizing with HA-PIST at TGN-like structures. C. In the presence of EGFP-harmonin, Myc-cadherin 23(-68) co-localizes with EGFP-harmonin, instead of co-localizing with HA-PIST at TGN-like structures. D. In the presence of EGFP-harmonin, Myc-cadherin 23(+68) co-localizes with EGFP-harmonin, as well as with HA-PIST at TGN-like structures. Myc-cadherin 23 was stained with mouse anti-Myc antibody then TRITC-conjugated goat anti-mouse secondary antibody. HA-PIST was stained with rabbit anti-PIST antibody then Cy5-conjugated goat anti-rabbit secondary antibody. Scale bar, 10 μm.

Mentions: MAGI-1, harmonin, and PIST can independently interact with cadherin 23 via a PDZ domain-mediated mechanism [4,10,11]. Given the fact that they all bind to the same binding site at the carboxyl-terminus of cadherin 23 (harmonin can also bind to an internal peptide of cadherin 23(-68) [22]), a single cadherin 23 protein might only be able to bind to either PIST, or MAGI-1, or harmonin. We consequently explored whether MAGI-1 or harmonin compete with PIST for binding cadherin 23, and furthermore, whether they are able to release cadherin 23 from the PIST-mediated trans-Golgi network retention. EGFP-MAGI-1 exists as protein aggregates in the cytoplasm when overexpressed in HEK293 cells (Figure 6B). When we co-expressed Myc-cadherin 23 and HA-PIST in presence of EGFP-MAGI-1, Myc-cadherin 23 (both +68 and -68 isoforms) co-localized with EGFP-MAGI-1 in the cytoplasm, and was no longer associated with HA-PIST in the trans-golgi network (Figure 6A,B). This suggests that MAGI-1 is able to competitively displace PIST from binding to cadherin 23, and that this competition releases the retention of cadherin 23 in the trans-golgi network.


PIST regulates the intracellular trafficking and plasma membrane expression of cadherin 23.

Xu Z, Oshima K, Heller S - BMC Cell Biol. (2010)

MAGI-1 and harmonin release cadherin 23 from PIST's retention in transfected HEK293 cells. A. Myc-tagged cadherin 23 co-localizes with HA-tagged PIST at TGN-like structures. B. In the presence of EGFP-MAGI-1c, Myc-cadherin 23 colocalizes in the cytoplasm with EGFP-MAGI-1c, instead of co-localizing with HA-PIST at TGN-like structures. C. In the presence of EGFP-harmonin, Myc-cadherin 23(-68) co-localizes with EGFP-harmonin, instead of co-localizing with HA-PIST at TGN-like structures. D. In the presence of EGFP-harmonin, Myc-cadherin 23(+68) co-localizes with EGFP-harmonin, as well as with HA-PIST at TGN-like structures. Myc-cadherin 23 was stained with mouse anti-Myc antibody then TRITC-conjugated goat anti-mouse secondary antibody. HA-PIST was stained with rabbit anti-PIST antibody then Cy5-conjugated goat anti-rabbit secondary antibody. Scale bar, 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2967513&req=5

Figure 6: MAGI-1 and harmonin release cadherin 23 from PIST's retention in transfected HEK293 cells. A. Myc-tagged cadherin 23 co-localizes with HA-tagged PIST at TGN-like structures. B. In the presence of EGFP-MAGI-1c, Myc-cadherin 23 colocalizes in the cytoplasm with EGFP-MAGI-1c, instead of co-localizing with HA-PIST at TGN-like structures. C. In the presence of EGFP-harmonin, Myc-cadherin 23(-68) co-localizes with EGFP-harmonin, instead of co-localizing with HA-PIST at TGN-like structures. D. In the presence of EGFP-harmonin, Myc-cadherin 23(+68) co-localizes with EGFP-harmonin, as well as with HA-PIST at TGN-like structures. Myc-cadherin 23 was stained with mouse anti-Myc antibody then TRITC-conjugated goat anti-mouse secondary antibody. HA-PIST was stained with rabbit anti-PIST antibody then Cy5-conjugated goat anti-rabbit secondary antibody. Scale bar, 10 μm.
Mentions: MAGI-1, harmonin, and PIST can independently interact with cadherin 23 via a PDZ domain-mediated mechanism [4,10,11]. Given the fact that they all bind to the same binding site at the carboxyl-terminus of cadherin 23 (harmonin can also bind to an internal peptide of cadherin 23(-68) [22]), a single cadherin 23 protein might only be able to bind to either PIST, or MAGI-1, or harmonin. We consequently explored whether MAGI-1 or harmonin compete with PIST for binding cadherin 23, and furthermore, whether they are able to release cadherin 23 from the PIST-mediated trans-Golgi network retention. EGFP-MAGI-1 exists as protein aggregates in the cytoplasm when overexpressed in HEK293 cells (Figure 6B). When we co-expressed Myc-cadherin 23 and HA-PIST in presence of EGFP-MAGI-1, Myc-cadherin 23 (both +68 and -68 isoforms) co-localized with EGFP-MAGI-1 in the cytoplasm, and was no longer associated with HA-PIST in the trans-golgi network (Figure 6A,B). This suggests that MAGI-1 is able to competitively displace PIST from binding to cadherin 23, and that this competition releases the retention of cadherin 23 in the trans-golgi network.

Bottom Line: PIST, a Golgi-associated, PDZ domain-containing protein, interacted with cadherin 23 via the PDZ domain of PIST and the C-terminal PDZ domain-binding interface (PBI) of cadherin 23.PIST binds cadherin 23 via its PDZ domain and retains cadherin 23 in trans-Golgi network.MAGI-1 and harmonin can compete with PIST for binding cadherin 23 and release cadherin 23 from PIST's retention.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Otolaryngology--Head & Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA. xuzg@sdu.edu.cn

ABSTRACT

Background: The atypical cadherin protein cadherin 23 (CDH23) is crucial for proper function of retinal photoreceptors and inner ear hair cells. As we obtain more and more information about the specific roles of cadherin 23 in photoreceptors and hair cells, the regulatory mechanisms responsible for the transport of this protein to the plasma membrane are largely unknown.

Results: PIST, a Golgi-associated, PDZ domain-containing protein, interacted with cadherin 23 via the PDZ domain of PIST and the C-terminal PDZ domain-binding interface (PBI) of cadherin 23. By binding to cadherin 23, PIST retained cadherin 23 in the trans-Golgi network of cultured cells. The retention was released when either of the two known cadherin 23-binding proteins MAGI-1 and harmonin was co-expressed. Similar to MAGI-1 and harmonin, PIST was detected in mouse inner ear sensory hair cells.

Conclusions: PIST binds cadherin 23 via its PDZ domain and retains cadherin 23 in trans-Golgi network. MAGI-1 and harmonin can compete with PIST for binding cadherin 23 and release cadherin 23 from PIST's retention. Our finding suggests that PIST, MAGI-1 and harmonin collaborate in intracellular trafficking of cadherin 23 and regulate the plasma membrane expression of cadherin 23.

Show MeSH
Related in: MedlinePlus