# MECHANISMS OF NERVE GROWTH CONE TURNING AND BRANCHING

> **NIH NIH R01** · UNIVERSITY OF MINNESOTA · 1994 · $153,573

## Abstract

A growth cone is the motile tip of an elongating nerve fiber, either an
axon or a dendrite.  Five behaviors of growth cones, migration, turning,
branching, retraction and synaptogenesis, are critical in formation of
neural circuits.  It is important to understand how growth cones migrate
and are regulated, because if growth cones fail to migrate properly
during development, brain structure, and consequent behavior is abnormal.
After injury to the nervous system, neural circuits are often destroyed,
and if axonal growth does not occur, paralysis, memory loss, and loss of
sensory function will result.  A better understanding of how axons grow
will help to develop strategies to promote axonal regeneration after
injuries to the nervous system.  The hypothesis has developed that a
growth cone is a sensory-effector machine that detects relevant
environmental cues and responds by regulating these critical behaviors.
The implication of this hypothesis is that growth cones navigate to their
targets.

Our lab has examined the cellular basis of the proposed sensory-effector
machinery of growth cones.  We will further probe this hypothesis through
experimental studies that pursue three specific aims.

1.  We will use high resolution light microscopy to record the behavior
of growth cones at boundaries between substrata of different
compositions.  We will examine filopodial and lamellipodial behavior at
boundaries regulates growth cone migration.  Growth cone activity at
boundaries will be analyzed, and related to growth cone-substratum
contacts.  We will also examine whether transmembrane signalling systems
mediate the regulatory effects of filopodia and lamellipodia.

2.  We will purify and characterize a species of myosin I that is greatly
enriched in growth cone particles from chick embryo brains.  This
mechanochemical enzyme may be important in the cytoskeletal activities
underlying growth cone migration, turning and branching.

3.  We will use three dimensional image reconstruction to examine the
relationships between stable microtubules and other components of neurons
and growth cones.  We will examine the hypothesis that stable
microtubules are critical to determining neuronal form.

## Key facts

- **NIH application ID:** 2197915
- **Project number:** 5R01HD019950-10
- **Recipient organization:** UNIVERSITY OF MINNESOTA
- **SAM.gov UEI:** KABJZBBJ4B54
- **Principal Investigator:** PAUL C. LETOURNEAU
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $153,573
- **Award type:** 5
- **Project period:** 1985-09-01 → 1996-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2197915

## Citation

> US National Institutes of Health, RePORTER application 2197915, MECHANISMS OF NERVE GROWTH CONE TURNING AND BRANCHING (5R01HD019950-10). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2197915. Licensed CC0.

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