Reactome | Substrate:LAMP2a:HSP90 polymerizes

Substrate:LAMP2a:HSP90 polymerizes

Stable Identifier

R-HSA-9624158

Type

Reaction [binding]

Species

Homo sapiens

Compartment

lysosomal lumen, lysosomal membrane

ReviewStatus

5/5

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Intracellular proteins are targeted for proteolytic degradation in the lysosome with the aid of chaperones. Heat shock cognate 71 kDa protein (HSPA8) acts as the constitutive chaperone that binds KFERQ-domain containing substrates in the cytosol. Consequently, the Hspa8:Substrate complex translocates from cytosol to lysosomal membrane where it binds to Lysosome-associated membrane glycoprotein 2 (LAMP2a). Subsequently, HSPA8 is released and Heat shock protein HSP 90 binds to the lysosomal luminal end of LAMP2a. Binding of HSP90 stabilizes LAMP2 to multimerize into a 700 kDa complex (Bandyopadhyay U et al. 2008). This facilitates the internalization of substrate into the lumen. Experiments confirming this binding were performed on rat models.

Literature References

PubMed ID	Title	Journal	Year
18644871	The chaperone-mediated autophagy receptor organizes in dynamic protein complexes at the lysosomal membrane Bandyopadhyay, U, Kaushik, S, Varticovski, L, Cuervo, AM	Mol. Cell. Biol.	2008
20797626	Identification of regulators of chaperone-mediated autophagy Bandyopadhyay, U, Sridhar, S, Kaushik, S, Kiffin, R, Cuervo, AM	Mol. Cell	2010