PDBsum entry 5itz

Structural protein

PDB id: 5itz

Contents

Protein chains

430 a.a.

420 a.a.

13 a.a.

127 a.a.

Ligands

GTP

GDP

LOC

Metals

_MG

Waters ×473

PDB id:

5itz

Name:

Structural protein

Title:

Crystal structure of the sac domain of cpap in a complex with tubulin and darpin

Structure:

Tubulin alpha-1b chain. Chain: a. Synonym: alpha-tubulin ubiquitous,tubulin k-alpha-1,tubulin alpha- ubiquitous chain. Tubulin beta-2b chain. Chain: b. Centromere protein j. Chain: d. Synonym: cenp-j,centrosomal p4.1-associated protein,lag-3-associated

Source:

Bos taurus. Bovine. Organism_taxid: 9913. Homo sapiens. Human. Organism_taxid: 9606. Gene: cenpj, cpap, lap, lip1. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Resolution:

2.20Å R-factor: 0.179 R-free: 0.217

Authors:

A.Sharma,M.O.Steinmetz

Key ref:

A.Sharma et al. (2016). Centriolar CPAP/SAS-4 Imparts Slow Processive Microtubule Growth. Dev Cell, 37, 362-376. PubMed id: 27219064 DOI: 10.1016/j.devcel.2016.04.024

Date:

17-Mar-16 Release date: 01-Jun-16

Protein chain

P81947  (TBA1B_BOVIN) -  Tubulin alpha-1B chain from Bos taurus

Seq: 451 a.a.

Struc: 430 a.a.

Protein chain

Q6B856  (TBB2B_BOVIN) -  Tubulin beta-2B chain from Bos taurus

Seq: 445 a.a.

Struc: 420 a.a.*

Protein chain

Q9HC77  (CENPJ_HUMAN) -  Centrosomal P4.1-associated protein from Homo sapiens

Seq: 1338 a.a.

Struc: 13 a.a.

Protein chain

No UniProt id for this chain

Struc: 127 a.a.

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: Chain A: E.C.3.6.5.- - ?????

DOI no: 10.1016/j.devcel.2016.04.024

Dev Cell 37:362-376 (2016)

PubMed id: 27219064

Centriolar CPAP/SAS-4 Imparts Slow Processive Microtubule Growth.

A.Sharma, A.Aher, N.J.Dynes, D.Frey, E.A.Katrukha, R.Jaussi, I.Grigoriev, M.Croisier, R.A.Kammerer, A.Akhmanova, P.Gönczy, M.O.Steinmetz.

ABSTRACT

Centrioles are fundamental and evolutionarily conserved microtubule-based organelles whose assembly is characterized by microtubule growth rates that are orders of magnitude slower than those of cytoplasmic microtubules. Several centriolar proteins can interact with tubulin or microtubules, but how they ensure the exceptionally slow growth of centriolar microtubules has remained mysterious. Here, we bring together crystallographic, biophysical, and reconstitution assays to demonstrate that the human centriolar protein CPAP (SAS-4 in worms and flies) binds and "caps" microtubule plus ends by associating with a site of β-tubulin engaged in longitudinal tubulin-tubulin interactions. Strikingly, we uncover that CPAP activity dampens microtubule growth and stabilizes microtubules by inhibiting catastrophes and promoting rescues. We further establish that the capping function of CPAP is important to limit growth of centriolar microtubules in cells. Our results suggest that CPAP acts as a molecular lid that ensures slow assembly of centriolar microtubules and, thereby, contributes to organelle length control.