These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Increase in intracellular pH induces phosphorylation of axonemal proteins for activation of flagellar motility in starfish sperm.
    Author: Nakajima A, Morita M, Takemura A, Kamimura S, Okuno M.
    Journal: J Exp Biol; 2005 Dec; 208(Pt 23):4411-8. PubMed ID: 16339861.
    Abstract:
    Increased intracellular pH ([pH]i) activates dynein in sea urchin and mammalian sperm and induces activation of flagellar motility. It is thought that cAMP-dependent protein phosphorylation is associated with motility activation through increasing [pH]i, but little attention has been given to the cAMP-independent phosphorylation also induced by the [pH]i increase. The present study demonstrates that the increase in [pH]i in starfish sperm induces the phosphorylation of axonemal proteins and activation of flagellar motility independently of cAMP. Flagellar motility of intact sperm was activated when the [pH]i was raised by addition of NH4Cl. Histidine, which is known to activate motility of starfish sperm, also raised the [pH]i during the motility activation. In addition, motility of demembranated sperm flagella was activated in a pH-dependent manner without cAMP. These results indicate that in starfish sperm it is the increase in [pH]i that induces activation of flagellar motility. Moreover, phosphorylation of axonemal proteins (of molecular mass 25, 32 and 45 kDa) was observed during the pH-dependent and cAMP-independent motility activation of demembranated sperm. This suggests that the increase in [pH]i regulates flagellar motility via cAMP-independent phosphorylation of axonemal proteins.
    [Abstract] [Full Text] [Related] [New Search]