Editing Pseudopodia (section)

==Morphology==
[[File:PseudopodiaFormsDavidPatterson.jpg|thumb|upright=1.3|The forms of pseudopodia, from left: polypodial and lobose; monopodial and lobose; filose; conical; reticulose; tapering actinopods; non-tapering actinopods]]

Pseudopods can be classified into several varieties according to the number of projections (monopodia and polypodia), and according to their appearance.

Some pseudopodial cells are able to use multiple types of pseudopodia depending on the situation. Most use a combination of [[lamellipodia]] and [[filopodia]] to migrate<ref name="Xue2010">{{cite journal |author=Xue F |display-authors=etal |year=2010 |title=Contribution of Filopodia to Cell Migration: A Mechanical Link between Protrusion and Contraction |journal=[[International Journal of Cell Biology]] |volume=2010 |pages=1–13 |doi=10.1155/2010/507821 |pmc=2910478 |pmid=20671957 |doi-access=free}}</ref> (e.g. metastatic cancer cells).<ref name="Machesky2012">{{cite journal |author=Machesky LM |display-authors=etal |year=2008 |title=Lamellipodia and filopodia in metastasis and invasion |journal=[[FEBS Letters]] |volume=582 |issue=14 |pages=2102–11 |doi=10.1016/j.febslet.2008.03.039 |pmid=18396168 |s2cid=46438967 |doi-access=}}</ref> Human [[foreskin]] fibroblasts can either use lamellipodia- or lobopodia-based migration in a 3D matrix depending on the matrix elasticity.<ref name="Petrie2012">{{cite journal |author=Petrie RJ |display-authors=etal |year=2012 |title=Nonpolarized signaling reveals two distinct modes of 3D cell migration |journal=[[Journal of Cell Biology]] |volume=197 |issue=3 |pages=439–455 |doi=10.1083/jcb.201201124 |pmc=3341168 |pmid=22547408}}</ref>

===Lamellipodia===
Lamellipodia are broad and flat pseudopodia used in locomotion.<ref name=":0" /> They are supported by microfilaments which form at the leading edge, creating a mesh-like internal network.<ref name="Bray2001">{{cite book |last=Bray |first=Dennis |author-link=Dennis Bray |date=2001 |title=Cell Movements: From molecules to motility second edition}}</ref>

===Filopodia===
Filopodia (or filose pseudopods) are slender and filiform with pointed ends, consisting mainly of [[ectoplasm (cell biology)|ectoplasm]]. These formations are supported by [[microfilament]]s which, unlike the filaments of lamellipodia with their net-like actin, form loose bundles by [[cross-link]]ing. This formation is partly due to bundling proteins such as [[fimbrin]]s and [[fascin]]s.<ref name="Bray2001" /><ref name="Vignjevic2006">{{Cite journal | author=Danijela Vignjevic|display-authors=etal| title=Role of fascin in filopodial protrusion| journal=Journal of Cell Biology | volume=174 | issue = 6  | year=2006 | pages=863–875 | doi=10.1083/jcb.200603013 | pmc=2064340 | pmid=16966425}}</ref>
Filopodia are observed in some animal cells: in part of [[Filosa]] ([[Rhizaria]]), in "[[Testaceafilosia]]", in [[Vampyrellidae]] and [[Pseudosporida]] ([[Rhizaria]]) and in [[Nucleariida]] ([[Opisthokonta]]).<ref name=":0" />

===Lobopodia===
Lobopodia (or lobose pseudopods) are bulbous, short, and blunt in form.<ref>{{Cite web|url=https://www.britannica.com/science/pseudopodium|title=Pseudopodium {{!}} cytoplasm|website=Encyclopedia Britannica|language=en|access-date=2018-12-16}}</ref> These finger-like, tubular pseudopodia contain both [[ectoplasm (cell biology)|ectoplasm]] and [[endoplasm]]. They can be found in different kind of cells, notably in [[Lobosa]] and other [[Amoebozoa]] and in some [[Heterolobosea]] ([[Excavata]]).

High-pressure lobopodia can also be found in human [[fibroblast]]s travelling through a complex network of 3D [[Extracellular matrix|matrix]] (e.g. mammalian [[dermis]], cell-derived matrix). Contrarily to other pseudopodia using the pressure exerted by actin polymerization on the membrane to extend, fibroblast lobopods use the nuclear piston mechanism consisting in pulling the nucleus via actomyosin contractility to push the [[cytoplasm]] that in turn push the membrane, leading to pseudopod formation. To occur, this lobopodia-based fibroblast migration needs [[Nesprin|nesprin 3]], [[integrin]]s, [[RHOA|RhoA]], [[Rho-associated protein kinase|ROCK]] and [[Myosin#Myosin II|myosin II]].
Otherwise, lobopods are often accompanied with small lateral [[Bleb (cell biology)|blebs]] forming along the side of the cell, probably due to the high intracellular pressure during lobopodia formation increasing the frequency of plasma membrane-cortex rupture.<ref name="Chengappa2018">{{Cite journal | author=Chengappa P |display-authors=etal | title=Chapter Seven - Intracellular Pressure: A Driver of Cell Morphology and Movement | journal=International Review of Cell and Molecular Biology | volume=337 | year=2018 | pages=185–211 | doi=10.1016/bs.ircmb.2017.12.005 |pmid=29551161 }}</ref><ref name="Petrie2012" /><ref name="Petrie2017">{{Cite journal | author=Petrie RJ |display-authors=etal | title=Activating the nuclear piston mechanism of 3D migration in tumor cells | journal=Journal of Cell Biology | volume=216 | issue = 1  | year=2017 | pages=93–100 | doi=10.1083/jcb.201605097 |pmid=27998990 |pmc=5223602 | doi-access=free }}</ref>

===Reticulopodia===
Reticulopodia (or reticulose pseudopods),<ref>{{cite web |url=http://www.eforams.icsr.agh.edu.pl/index.php/Reticulopodia |title=Reticulopodia |website=eForams |access-date=2005-12-30 |url-status=dead |archive-url=https://web.archive.org/web/20070717192718/http://www.eforams.icsr.agh.edu.pl/index.php/Reticulopodia |archive-date=2007-07-17 }}</ref> are complex formations in which individual pseudopods are merged and form irregular nets. The primary function of reticulopodia, also known as myxopodia, is food ingestion, with locomotion a secondary function. Reticulopods are typical of [[Foraminifera]], [[Chlorarachnea]], ''[[Gromia]]'' and ''[[Filoreta]]'' (Rhizaria).<ref name=":0" />

===Axopodia===
Axopodia (also known as actinopodia) are narrow pseudopodia containing complex arrays of [[microtubule]]s enveloped by cytoplasm. Axopodia are mostly responsible for phagocytosis by rapidly retracting in response to physical contact. These pseudopodia are primarily food-collecting structures, but also provide a means of hydrological transportation via the expansion of their surface areas. They are observed in "[[Radiolaria]]"  and "[[Heliozoa]]".<ref name=":0" />