# MECHANISMS OF MOTILITY AND CHEMOTAXIS IN BACTERIA

> **NIH NIH R01** · CALIFORNIA INSTITUTE OF TECHNOLOGY · 1993 · $240,253

## Abstract

All cells have the ability to detect and respond appropriately to small
changes in the concentration of a variety of chemical signals.  In the
microbial world, bacterial behavior, sporulation, pathogenesis, and gene
regulation all incorporate a series of steps that involve signal
transduction.  We have shown that in bacterial chemotaxis a complex
information processing system includes a transmembrane receptor protein
which is capable of binding ligand, transmitting information across the
membrane and initiating an citation and an adaptation process. Excitation
involves the activation or inactivation of a protein kinase and the
regulation of phosphorylated levels of the CheY protein.  CheY regulates
the "effector" element in this system, a "switch" which in turn controls
the direction of flagellar rotation.  The adaptation mechanism involves
the modification of the receptor and the modulation of its ability to
influence kinase activity.  Homologues of the chemotaxis kinase and
regulator proteins are found in many other microbial systems and the
entire information processing circuit is analogous to signal transduction
systems in eukaryotic organisms.  This grant focuses on the continued
detailed study of the components of the chemotaxis system and how the
properties of the information processing system are derived from the
interactions between their components.  We will probe the nature of the
transmembrane regions of the receptor using mutagenesis and crosslinking
to understand the process of transmembrane transmission of information.
Functional domains of the transmembrane receptor will be overproduced and
their interactions with the kinase coupling protein and other components
of the chemotaxis system will be studied in a reconstitution system.  We
will also reconstitute the effector portion of the pathway and study the
interaction of the CheY protein with the flagellar "switch".  Details of
these processes will be directly applicable to understanding other
homologous systems in bacteria and eventually will allow us to understand
general "design" strategies involved in biological information processing
systems.

## Key facts

- **NIH application ID:** 3128655
- **Project number:** 5R01AI019296-12
- **Recipient organization:** CALIFORNIA INSTITUTE OF TECHNOLOGY
- **SAM.gov UEI:** U2JMKHNS5TG4
- **Principal Investigator:** MELVIN SIMON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $240,253
- **Award type:** 5
- **Project period:** 1982-08-01 → 1997-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3128655

## Citation

> US National Institutes of Health, RePORTER application 3128655, MECHANISMS OF MOTILITY AND CHEMOTAXIS IN BACTERIA (5R01AI019296-12). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3128655. Licensed CC0.

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