title: Tuning sperm chemotaxis.
abstract: Sperm chemotaxis is a long-term puzzle and most of our knowledge comes from studying marine animals that are external fertilizers. Sperm are attracted by diffusible chemical factors (chemoattractants) released from the egg which redirect their swimming paths towards their source. This redirection is driven by increases in flagellar curvature that correlate with transient flagellar Ca(2+) increases. Recent experimental and modelling results provide insights into the signal flow underlying the translation of an external chemical gradient into an intracellular molecular and motor response. A fundamental element of sea-urchin sperm chemotaxis lies in the ability of these cells to suppress Ca(2+)-mediated increases in flagellar curvature while experiencing an increasing chemoattractant gradient. The article considers this new evidence and summarizes the known underlying cellular mechanisms and behavioural strategies that sperm use to locate and fertilize the oocyte.
authors.affiliation: Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad, 2001 Col. Chamilpa, Cuernavaca, Morelos, Mexico. adanog@ibt.unam.mx
authors.forename: Adán
authors.initials: A
authors.lastname: Guerrero
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Wood
authors.forename: Takuya
authors.initials: T
authors.lastname: Nishigaki
authors.forename: Jorge
authors.initials: J
authors.lastname: Carneiro
authors.forename: Alberto
authors.initials: A
authors.lastname: Darszon
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000235:genetics / Q000502:physiology; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology*; D005306:Fertilization / Q000235:genetics / Q000502:physiology; D008297:Male; D012617:Sea Urchins / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D013081:Sperm Motility / Q000235:genetics / Q000502:physiology; D013094:Spermatozoa / Q000378:metabolism* / Q000502:physiology*