Retrograde flow rate is increased in growth cones from myosin IIB knockout mice

Michael E. Brown, Paul C. Bridgman

Research output: Contribution to journalReview articlepeer-review

71 Scopus citations


Growth cones of myosin-IIB-knockout mice have reduced outgrowth rates and traction force. There is a close relationship between traction force, retrograde flow and forward advance of growth cones. All three activities appear to be at least partially myosin dependent. Therefore, we have now tested for differences in retrograde flow rates between growth cones from myosin-IIB-knockout mice and their normal littermates. By placing nerve-growth-factor-coated silica beads on the surface of growth cones with laser tweezers, or by tracking GFP-myosin HA spots, we found that the retrograde flow rate was increased more than two fold in the knockout growth cones compared with the wild type. These data suggest that both myosin IIA and IIB normally contribute to retrograde flow and the properties of the flow are strongly influenced by myosin IIB because of its location and abundance. However, in the absence of myosin IIB, myosin IIA takes over this function. The change in retrograde flow rate may reflect the difference in functional properties of these two myosins. Knockout growth cones also exhibited reduced stability of lamellipodia, possibly as a partial consequence of this increased retrograde flow rate. In addition, microtubules penetrated a shorter distance into filopodia, which suggests that the increase in flow rate may adversely affect the microtubule-dependent maturation of filopodia. Taken together these data support the idea that the forward advance of the growth cone is myosin II dependent and involves multiple myosin II isoforms.

Original languageEnglish
Pages (from-to)1087-1094
Number of pages8
JournalJournal of cell science
Issue number6
StatePublished - Mar 15 2003


  • Actin
  • Motility
  • Nerve outgrowth

Fingerprint Dive into the research topics of 'Retrograde flow rate is increased in growth cones from myosin IIB knockout mice'. Together they form a unique fingerprint.

Cite this