6V97

Kindlin-3 double deletion mutant short form

Summary for 6V97

• Entry DOI: 10.2210/pdb6v97/pdb
• Descriptor: Fermitin family homolog 3 (2 entities in total)
• Functional Keywords: integrin binding protein, blood clotting
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 2
• Total formula weight: 107772.91

Authors

Xu, Z.,Zhang, T.L.,Xu, Z.,Sun, J.J.,Ding, J.P.,Ma, Y.Q. (deposition date: 2019-12-13, release date: 2020-07-22, Last modification date: 2023-10-11)

Primary citation

Sun, J.,Xiao, D.,Ni, Y.,Zhang, T.,Cao, Z.,Xu, Z.,Nguyen, H.,Zhang, J.,White, G.C.,Ding, J.,Ma, Y.Q.,Xu, Z.
Structure basis of the FERM domain of kindlin-3 in supporting integrin alpha IIb beta 3 activation in platelets.
Blood Adv, 4:3128-3135, 2020

PubMed Abstract: Kindlin-3, a protein 4.1, ezrin, radixin, and moesin (FERM) domain-containing adaptor in hematopoietic cells, is essentially required for supporting the bidirectional integrin αIIbβ3 signaling in platelets by binding to the integrin β3 cytoplasmic tail. However, the structural details of kindlin-3's FERM domain remain unknown. In this study, we crystalized the kindlin-3's FERM domain protein and successfully solved its 3-dimensional structure. The structure shows that the 3 kindlin-3's FERM subdomains (F1, F2, and F3) compact together and form a cloverleaf-shaped conformation, which is stabilized by the binding interface between the F1 and F3 subdomains. Interestingly, the FERM domain of kindlin-3 exists as a monomer in both crystal and solution, which is different from its counterpart in kindlin-2 that is able to form a F2 subdomain-swapped dimer; nonetheless, dimerization is required for kindlin-3 to support integrin αIIbβ3 activation, indicating that kindlin-3 may use alternative mechanisms for formation of a functional dimer in cells. To evaluate the functional importance of the cloverleaf-like FERM structure in kindlin-3, structure-based mutations were introduced into kindlin-3 to disrupt the F1/F3 interface. The results show that integrin αIIbβ3 activation is significantly suppressed in platelets expressing the kindlin-3 mutant compared with those expressing wild-type kindlin-3. In addition, introduction of equivalent mutations into kindlin-1 and kindlin-2 also significantly compromises their ability to support integrin αIIbβ3 activation in CHO cells. Together, our findings suggest that the cloverleaf-like FERM domain in kindlins is structurally important for supporting integrin αIIbβ3 activation.

PubMed: 32649767
DOI: 10.1182/bloodadvances.2020001575

Experimental method

X-RAY DIFFRACTION (2.381 Å)