Harold Paul Erickson

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James B. Duke Professor of Medicine

Cytoskeleton: It is now clear that the actin and microtubule cytoskeleton originated in bacteria. Our major research is on FtsZ, the bacterial tubulin homolog, which assembles into a contractile ring that divides the bacterium. We have studied FtsZ assembly in vitro, and found that it assembles into thin protofilaments. Dozens of these protofilaments are further clustered to form the contractile Z-ring in vivo. Recent discoveries include:

• The Z ring is very dynamic, exchanging subunits with a half time of 8 s.
• Reconstitution of Z rings in vitro. We provided FtsZ with a membrane tether, and found that when incorporated inside liposomes, membrane-targeted FtsZ can assemble Z rings without any other proteins.
• These reconstituted Z rings can also generate a constriction force on the membranes, again without any other proteins (no motor molecules).
• The constriction force is generated by a curved conformation of the protofilaments generating a bending force on the membrane.
• Negative stain EM of artificial Z rings shows ribbons of protofilaments, contradicting the prevailing view from cryoEM tomography of scattered protofilaments

Our long term goals are two-fold. First, to understand the mechanism of bacterial cell division. Second, to learn basic principles of assembly and mechanics that will apply to both FtsZ and tubulin.

Extracellular Matrix: A second interest of our lab is extracellular matrix and cell adhesion, focusing now on fibronectin. We have discovered that the FN matrix is very elastic, with fibrils stretching up to four-fold over their relaxed length. We have two possible mechanisms to explain the elasticity of FN, and are currently developing experimental tests to resolve the mechanism. We are also studying the molecular structure of FN matrix fibrils and the mechanism of assembly. Assembly of "super FN" is providing important new insights.

Appointments and Affiliations

  • James B. Duke Professor of Medicine
  • Professor of Cell Biology
  • Professor of Biochemistry
  • Member of the Duke Cancer Institute

Contact Information:

Education:

  • Ph.D. Johns Hopkins University, 1968

Courses Taught:

  • BIOCHEM 393: Research Independent Study
  • BIOCHEM 593: Research Independent Study
  • CELLBIO 493: Research Independent Study
  • CELLBIO 710: Papers and Grant Writing Workshop
  • NEUROBIO 710: Papers and Grant Writing Workshop

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