The role of kinesin, dynein and microtubules in pancreatic secretion.
The regulated secretion of pancreatic zymogens depends on a functional cytoskeleton and intracellular vesicle transport. To study the dynamics of tubulin and its motor proteins dynein and kinesin during secretion in pancreatic acinar cells, we infused rats with 0.1 mug/kg/h caerulein. Electron and fluorescence microscopy detected neither dynein nor kinesin at the apical secretory pole, nor on the surface of mature zymogen granules. After 30 min of secretagogue stimulation, kinesin and the Golgi marker protein 58 K were reallocated towards the apical plasma membrane and association of kinesin with tubulin was enhanced. Disruption of acinar cell microtubules had no effect on initial caerulein-induced amylase release but completely blocked secretion during a second stimulus. Our results suggest that mature zymogen granule exocytosis is independent of intact microtubules, kinesin and dynein. However, microtubule-dependent mechanisms seem to be important for the replenishment of secretory vesicles by redistribution of Golgi elements towards the apical cell pole.
Schnekenburger
Jürgen
J
Department of Medicine B, Westfälische Wilhelms-University, Domagkstr. 3A, 48149 Münster, Germany. schnekenburger@uni-muenster.de
Weber
Ina-Alexandra
IA
Hahn
Daniela
D
Buchwalow
Igor
I
Krüger
Burkhard
B
Albrecht
Elke
E
Domschke
Wolfram
W
Lerch
Markus M
MM
D000681:Amylases / Q000378:metabolism; D000818:Animals; D002108:Ceruletide / Q000378:metabolism; D003078:Colchicine / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000737:chemistry / Q000378:metabolism; D004398:Dyneins / Q000378:metabolism*; D004792:Enzyme Precursors / Q000378:metabolism; D005089:Exocytosis / Q000502:physiology; D006056:Golgi Apparatus / Q000378:metabolism; D016547:Kinesins / Q000378:metabolism*; D008297:Male; D016253:Microscopy, Immunoelectron; D008870:Microtubules / Q000378:metabolism*; D020409:Molecular Motor Proteins / Q000378:metabolism; D010179:Pancreas / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010189:Pancreatic Juice / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014404:Tubulin / Q000302:isolation & purification / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology
D004792:Enzyme Precursors; D020409:Molecular Motor Proteins; D014404:Tubulin; D050257:Tubulin Modulators; D002108:Ceruletide; D000681:Amylases; D004398:Dyneins; D016547:Kinesins; D003078:Colchicine