The major hormonal product of the coupling reaction is the molecule thyroxine (T4), which is formed when two molecules of DIT are joined together; the thyroxine then remains part of the thyroglobulin molecule.

TLS Online TPP Program

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#Unit 2. Cellular Organization

In one minute, each NPC is estimated to import 60,000 protein molecules into the nucleus, while exporting 50–250 mRNA molecules, 10–20 ribosomal subunits, & 1000 tRNAs out of the nucleus.

TLS Online TPP Program

#Id: 7777

#Unit 2. Cellular Organization

An NPC is made up of many copies of some 30 different proteins called nucleoporins.

TLS Online TPP Program

#Id: 7778

#Unit 2. Cellular Organization

Eight approximately 100-nm long filaments extend into the nucleoplasm with the distal ends of these filaments joined by a terminal ring, forming a structure called the nuclear basket.

TLS Online TPP Program

#Id: 7779

#Unit 2. Cellular Organization

The nucleoporins are of three types: 

a. Structural nucleoporins

b. Membrane nucleoporins

c. FG-nucleoporins

TLS Online TPP Program

#Id: 7780

#Unit 2. Cellular Organization

A set of seven structural nucleoporins forms a Y-shaped structure about the size of the ribosome, known as the Y complex.

TLS Online TPP Program

#Id: 7781

#Unit 2. Cellular Organization

A structural motif repeated several times within the Y-complex is closely related to a structure found in the COPII proteins that drive the formation of coated vesicles within cells.