October 19, 2012

Anchor sequences determine protein orientation

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KEY TERMS: An anchor   ( stop-transfer ) (often referred to as a "transmembrane anchor") is a segment of a transmembrane pr...
October 18, 2012

Proteins reside in membranes by means of hydrophobic regions

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KEY TERMS: The transmembrane region   ( transmembrane domain ) is the part of a protein that spans the membrane bilayer. It is hydr...

Reverse translocation sends proteins to the cytosol for degradation

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KEY TERMS: Retrograde translocation   ( Reverse translocation ) is the translocation of a protein from the lumen of the ER to the cyt...

Translocation requires insertion into the translocon and (sometimes) a ratchet in the ER

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KEY CONCEPTS: The ribosome, SRP, and SRP receptor are sufficient to insert a nascent protein into a translocon. Proteins that are in...

The translocon forms a pore

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KEY TERMS: A translocon is a discrete structure in a membrane that forms a channel through which (hydrophilic) proteins may pass. ...

The SRP interacts with the SRP receptor

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KEY TERMS: The Alu domain comprises the parts of the 7S RNA of the SRP that are related to Alu RNA. The S domain is the sequence ...

The signal sequence interacts with the SRP

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KEY TERMS: Protein translocation describes the movement of a protein across a membrane. This occurs across the membranes of organel...

Signal sequences initiate translocation

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KEY TERMS: Protein sorting   ( targeting ) is the direction of different types of proteins for transport into or between specific...
October 16, 2012

Hsp60/GroEL forms an oligomeric ring structure

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KEY CONCEPTS: Hsp60/GroEL forms an oligomeric structure consisting of 14 subunits arranged in two inverted heptameric rings. A GroES...

The Hsp70 family is ubiquitous

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KEY CONCEPTS: Hsp70 is a chaperone that functions on target proteins in conjunction with DnaJ and GrpE. Members of the Hsp70 family ...