Global Regulation web biosci utexas edu

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          SIGNAL TRANSDUCTION
• BACTERIA SENSE CHANGE IN ENVIRONMENT AND
  RESPOND TO IT

• TWO COMPONENT SIGNAL TRANSDUCTION SYSTEM
  PHOSPHO-RELAY SYSTEM

     SENSOR KINASE
        DETECTS CHANGE IN ENVIRONMENT (e.g.,
             FOOD)
        TRANSMITS SIGNAL TO RESPONSE
          REGULATOR BY PHOSPHORYLATING IT
         KINASES TRANSFER PHOSPHORYL GROUPS
          (KINASES CAN PHOSPHORYLATE
          THEMSELVES)

     RESPONSE REGULATOR
         PHOSPHORYLATED PROTEIN
        CONTROLS TRANSCRIPTION / OR PROCESS
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GLOBAL REGULATORY SYSTEMS
       REGULONS - MANY GENES AND OPERONS CONTROLLED
              SIMULTANEOUSLY
       ALLOW CELLS TO RESPOND TO CHANGING ENVIRONMENTS
       HEAT SHOCK, DAMAGE TO CHROMOSOME,
              AVAILABILITY OF FOOD (CHEMOTAXIS TO FOOD)
EXAMPLES
1. CATABOLITE REPRESSION SYSTEM: SEVERAL OPERONS INVOLVED IN
SUGAR CATABOLISM REQUIRE cAMP-CAP POSITIVE ACTIVATOR TO TURN ON
TRANSCRIPTION. [THIS SYSTEM IS THE CATABOLITE REPRESSION REGULON]
       LACTOSE, ARABINOSE, GALACTOSE, RIBOSE OPERONS
       LACTOSE CONVERTED TO GLUCOSE & GALACTOSE
       L-ARABINOSE CONVERTED TO D-XYLULOSE-5-PO4
       GALACTOSE CONVERTED TO GLUCOSE-1-PO4
       RIBOSE CONVERTED TO XYLULOSE-5-PO4
       [NOTE: XYLULOSE-5-PO4 CAN BE CONVERTED INTO
       FRUCTOSE-6-PO4 WHICH FEEDS INTO GLYCOLYSIS]
 GLUCOSE (INDIRECTLY) INHIBITS cAMP SYNTHESIS AND GLUCOSE
PRESENCE IN THE MEDIUM PREVENTS TURNING ON ANY OF THE SUGAR
OPERONS
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2. ENDOSPORE FORMATION (IN RESPONSE TO NUTRIENT DEPLETION)




   STAGE 0            STAGE I         STAGE II          STAGE III
VEGETATIVE CELL        AXIAL        ASYMMETRIC        ENGULFMENT
                  FILAMENTATION      SEPTATION
                      OF DNA




    STAGE IV        STAGE V           STAGE VI         STAGE VII
    CORTEX           COAT            MATURATION       MOTHER CELL
[PEPTIDOGLYCAN]    SYNTHESIS      [FULLY RESISTANT]      LYSIS
   SYNTHESIS
                                                                  4
                SIGNAL TRANSDUCTION TO
                  INITIATE SPORULATION

                       SENSOR
PHOSPHORY-
LATES ITSELF
                      KINASE - P
 DUE TO GTP                        SpoOF
  CONCEN- SENSOR
  TRATION
   DROP      KINASE
                                              SpoOB - P
                          SpoOF - P
                                                          SpoOA
                                      SpoOB
                        PHOSPHO-
                          RELAY
                        PROTEINS
                                                  SpoOA - P
                                                  RESPONSE
                                                 REGULATOR =
                                              MASTER CONTROLLER
    RESPONSE REGULATOR                    5
         SpoOA-P
ACTS WITH RNA Pol- s A

BINDS OA SITES NEAR s    A   PROMOTERS
         TTTGTCGAAAAA
CONTROLS REGULON OF 121 GENES
         30 INDIVIDUAL
         24 OPERONS

ACTIVATES GENES FOR:
  AXIAL FILAMENT ORGANIZING
  ASYMMETRIC SEPTATION
  25 TRANSCRIPTION FACTORS
     s F - FORESPORE EARLY
     s E - MOTHER CELL EARLY
INHIBITS GENES FOR:
  DNA REPLICATION; MOTILITY; CHEMOTAXIS
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       SIGMA CASCADE – INITIATED BY SpoOA-P
TIME
           FORESPORE
            sF CONTROLS:
                     SPORE RESISTANCE
                       PROTEINS
                     sG   [INACTIVE]
                     PRO – sE PROTEASE


          MOTHER CELL

            PRO -   sE
                              7




PRO sE PROTEASE SECRETED
  INTO MOTHER CELL FROM
  FORESPORE

ACTIVATES sE BY PROTEOLYTIC
  CLEAVAGE
                               8




sE ACTIVATES REGULON OF ~273
   GENES / OPERON
      ENGULFMENT TRIGGERED
      CORTEX [PEPTIDOGLYCAN]
        SYNTHESIS ENZYMES
      ACTIVATOR OF sG
      PRO- sK
                                              9
ENGULFMENT



       sG ACTIVATOR SECRETES INTO FORESPORE
         FROM MOTHER CELL ACTIVATES sG
          sG ACTIVATES:
             • SPORE PROTECTION PROTEINS -
                 UV REPAIR
                 DNA BINDING (PROTECTION)
             • GERMINATION ENZYMES
             • ACTIVATOR OF PRO- sK

                      PRO- sK
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• PRO- sK ACTIVATOR SECRETED INTO
   MOTHER CELL FROM FORESPORE
• ACTIVATES sK
   sK REGULON - 75 GENES
   COAT SYNTHESIS AND ASSEMBLY
   SUGARS FOR ATTACHMENT- SURFACE
    OF SPORE
   ANOTHER DNA BINDING REGULATORY
    PROTEIN
       REPRESSES ~1/2 sK REGULON
       ACTIVATES
           GERMINATION ENZYME
              GENES
           MOTHER CELL LYSIS
              ENZYMES

				
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posted:4/23/2011
language:English
pages:12